-This is tar.info, produced by makeinfo version 4.13 from tar.texi.
+This is tar.info, produced by makeinfo version 5.9.93 from tar.texi.
-This manual is for GNU `tar' (version 1.28, 22 July 2014), which
+This manual is for GNU 'tar' (version 1.29, 14 April 2016), which
creates and extracts files from archives.
- Copyright (C) 1992, 1994-1997, 1999-2001, 2003-2013 Free Software
+ Copyright (C) 1992, 1994-1997, 1999-2001, 2003-2016 Free Software
Foundation, Inc.
Permission is granted to copy, distribute and/or modify this
document under the terms of the GNU Free Documentation License,
Version 1.3 or any later version published by the Free Software
Foundation; with the Invariant Sections being "GNU General Public
- License", with the Front-Cover Texts being "A GNU Manual", and
- with the Back-Cover Texts as in (a) below. A copy of the license
- is included in the section entitled "GNU Free Documentation
- License".
-
- (a) The FSF's Back-Cover Text is: "You have the freedom to copy
- and modify this GNU manual."
+ License", with the Front-Cover Texts being "A GNU Manual", and with
+ the Back-Cover Texts as in (a) below. A copy of the license is
+ included in the section entitled "GNU Free Documentation License".
+ (a) The FSF's Back-Cover Text is: "You have the freedom to copy and
+ modify this GNU manual."
INFO-DIR-SECTION Archiving
START-INFO-DIR-ENTRY
* Tar: (tar). Making tape (or disk) archives.
INFO-DIR-SECTION Individual utilities
START-INFO-DIR-ENTRY
-* tar: (tar)tar invocation. Invoking GNU `tar'.
+* tar: (tar)tar invocation. Invoking GNU 'tar'.
END-INFO-DIR-ENTRY
\1f
GNU tar: an archiver tool
*************************
-This manual is for GNU `tar' (version 1.28, 22 July 2014), which
+This manual is for GNU 'tar' (version 1.29, 14 April 2016), which
creates and extracts files from archives.
- Copyright (C) 1992, 1994-1997, 1999-2001, 2003-2013 Free Software
+ Copyright (C) 1992, 1994-1997, 1999-2001, 2003-2016 Free Software
Foundation, Inc.
Permission is granted to copy, distribute and/or modify this
document under the terms of the GNU Free Documentation License,
Version 1.3 or any later version published by the Free Software
Foundation; with the Invariant Sections being "GNU General Public
- License", with the Front-Cover Texts being "A GNU Manual", and
- with the Back-Cover Texts as in (a) below. A copy of the license
- is included in the section entitled "GNU Free Documentation
- License".
+ License", with the Front-Cover Texts being "A GNU Manual", and with
+ the Back-Cover Texts as in (a) below. A copy of the license is
+ included in the section entitled "GNU Free Documentation License".
- (a) The FSF's Back-Cover Text is: "You have the freedom to copy
- and modify this GNU manual."
+ (a) The FSF's Back-Cover Text is: "You have the freedom to copy and
+ modify this GNU manual."
The first part of this master menu lists the major nodes in this Info
document. The rest of the menu lists all the lower level nodes.
* Index of Command Line Options::
* Index::
- --- The Detailed Node Listing ---
+ -- The Detailed Node Listing --
Introduction
* Book Contents:: What this Book Contains
* Definitions:: Some Definitions
-* What tar Does:: What `tar' Does
-* Naming tar Archives:: How `tar' Archives are Named
-* Authors:: GNU `tar' Authors
+* What tar Does:: What 'tar' Does
+* Naming tar Archives:: How 'tar' Archives are Named
+* Authors:: GNU 'tar' Authors
* Reports:: Reporting bugs or suggestions
-Tutorial Introduction to `tar'
+Tutorial Introduction to 'tar'
* assumptions::
* stylistic conventions::
-* basic tar options:: Basic `tar' Operations and Options
+* basic tar options:: Basic 'tar' Operations and Options
* frequent operations::
* Two Frequent Options::
* create:: How to Create Archives
* extracting untrusted archives::
* failing commands::
-Invoking GNU `tar'
+Invoking GNU 'tar'
* Synopsis::
* using tar options::
* Old Options:: Old Option Style
* Mixing:: Mixing Option Styles
-All `tar' Options
+All 'tar' Options
* Operation Summary::
* Option Summary::
* Short Option Summary::
+* Position-Sensitive Options::
-GNU `tar' Operations
+GNU 'tar' Operations
* Basic tar::
* Advanced tar::
* Applications::
* looking ahead::
-Advanced GNU `tar' Operations
+Advanced GNU 'tar' Operations
* Operations::
* append::
* delete::
* compare::
-How to Add Files to Existing Archives: `--append'
+How to Add Files to Existing Archives: '--append'
* appending files:: Appending Files to an Archive
* multiple::
* how to update::
-Options Used by `--create'
+Options Used by '--create'
* override:: Overriding File Metadata.
+* Extended File Attributes::
* Ignore Failed Read::
-Options Used by `--extract'
+Options Used by '--extract'
* Reading:: Options to Help Read Archives
-* Writing:: Changing How `tar' Writes Files
+* Writing:: Changing How 'tar' Writes Files
* Scarce:: Coping with Scarce Resources
Options to Help Read Archives
* read full records::
* Ignore Zeros::
-Changing How `tar' Writes Files
+Changing How 'tar' Writes Files
* Dealing with Old Files::
* Overwrite Old Files::
Performing Backups and Restoring Files
-* Full Dumps:: Using `tar' to Perform Full Dumps
-* Incremental Dumps:: Using `tar' to Perform Incremental Dumps
+* Full Dumps:: Using 'tar' to Perform Full Dumps
+* Incremental Dumps:: Using 'tar' to Perform Incremental Dumps
* Backup Levels:: Levels of Backups
* Backup Parameters:: Setting Parameters for Backups and Restoration
* Scripted Backups:: Using the Backup Scripts
* General-Purpose Variables::
* Magnetic Tape Control::
* User Hooks::
-* backup-specs example:: An Example Text of `Backup-specs'
+* backup-specs example:: An Example Text of 'Backup-specs'
-Choosing Files and Names for `tar'
+Choosing Files and Names for 'tar'
* file:: Choosing the Archive's Name
* Selecting Archive Members::
* Compression:: Using Less Space through Compression
* Attributes:: Handling File Attributes
-* Portability:: Making `tar' Archives More Portable
-* cpio:: Comparison of `tar' and `cpio'
+* Portability:: Making 'tar' Archives More Portable
+* cpio:: Comparison of 'tar' and 'cpio'
Using Less Space through Compression
Creating and Reading Compressed Archives
-* lbzip2:: Using lbzip2 with GNU `tar'.
+* lbzip2:: Using lbzip2 with GNU 'tar'.
-Making `tar' Archives More Portable
+Making 'tar' Archives More Portable
* Portable Names:: Portable Names
* dereference:: Symbolic Links
* Checksumming:: Checksumming Problems
* Large or Negative Values:: Large files, negative time stamps, etc.
* Other Tars:: How to Extract GNU-Specific Data Using
- Other `tar' Implementations
+ Other 'tar' Implementations
-GNU `tar' and POSIX `tar'
+GNU 'tar' and POSIX 'tar'
* PAX keywords:: Controlling Extended Header Keywords.
-How to Extract GNU-Specific Data Using Other `tar' Implementations
+How to Extract GNU-Specific Data Using Other 'tar' Implementations
* Split Recovery:: Members Split Between Volumes
* Sparse Recovery:: Sparse Members
Many Archives on One Tape
* Tape Positioning:: Tape Positions and Tape Marks
-* mt:: The `mt' Utility
+* mt:: The 'mt' Utility
Using Multiple Tapes
* GNU Free Documentation License:: License for copying this manual
+
\1f
File: tar.info, Node: Introduction, Next: Tutorial, Prev: Top, Up: Top
1 Introduction
**************
-GNU `tar' creates and manipulates "archives" which are actually
+GNU 'tar' creates and manipulates "archives" which are actually
collections of many other files; the program provides users with an
organized and systematic method for controlling a large amount of data.
The name "tar" originally came from the phrase "Tape ARchive", but
* Book Contents:: What this Book Contains
* Definitions:: Some Definitions
-* What tar Does:: What `tar' Does
-* Naming tar Archives:: How `tar' Archives are Named
-* Authors:: GNU `tar' Authors
+* What tar Does:: What 'tar' Does
+* Naming tar Archives:: How 'tar' Archives are Named
+* Authors:: GNU 'tar' Authors
* Reports:: Reporting bugs or suggestions
\1f
The first part of this chapter introduces you to various terms that will
recur throughout the book. It also tells you who has worked on GNU
-`tar' and its documentation, and where you should send bug reports or
+'tar' and its documentation, and where you should send bug reports or
comments.
The second chapter is a tutorial (*note Tutorial::) which provides a
-gentle introduction for people who are new to using `tar'. It is meant
-to be self-contained, not requiring any reading from subsequent
-chapters to make sense. It moves from topic to topic in a logical,
-progressive order, building on information already explained.
+gentle introduction for people who are new to using 'tar'. It is meant
+to be self-contained, not requiring any reading from subsequent chapters
+to make sense. It moves from topic to topic in a logical, progressive
+order, building on information already explained.
Although the tutorial is paced and structured to allow beginners to
-learn how to use `tar', it is not intended solely for beginners. The
+learn how to use 'tar', it is not intended solely for beginners. The
tutorial explains how to use the three most frequently used operations
-(`create', `list', and `extract') as well as two frequently used
-options (`file' and `verbose'). The other chapters do not refer to the
-tutorial frequently; however, if a section discusses something which is
-a complex variant of a basic concept, there may be a cross-reference to
-that basic concept. (The entire book, including the tutorial, assumes
-that the reader understands some basic concepts of using a Unix-type
-operating system; *note Tutorial::.)
+('create', 'list', and 'extract') as well as two frequently used options
+('file' and 'verbose'). The other chapters do not refer to the tutorial
+frequently; however, if a section discusses something which is a complex
+variant of a basic concept, there may be a cross-reference to that basic
+concept. (The entire book, including the tutorial, assumes that the
+reader understands some basic concepts of using a Unix-type operating
+system; *note Tutorial::.)
The third chapter presents the remaining five operations, and
-information about using `tar' options and option syntax.
+information about using 'tar' options and option syntax.
The other chapters are meant to be used as a reference. Each chapter
presents everything that needs to be said about a specific topic.
One of the chapters (*note Date input formats::) exists in its
entirety in other GNU manuals, and is mostly self-contained. In
addition, one section of this manual (*note Standard::) contains a big
-quote which is taken directly from `tar' sources.
+quote which is taken directly from 'tar' sources.
- In general, we give both long and short (abbreviated) option names
-at least once in each section where the relevant option is covered, so
-that novice readers will become familiar with both styles. (A few
-options have no short versions, and the relevant sections will indicate
-this.)
+ In general, we give both long and short (abbreviated) option names at
+least once in each section where the relevant option is covered, so that
+novice readers will become familiar with both styles. (A few options
+have no short versions, and the relevant sections will indicate this.)
\1f
File: tar.info, Node: Definitions, Next: What tar Does, Prev: Book Contents, Up: Introduction
1.2 Some Definitions
====================
-The `tar' program is used to create and manipulate `tar' archives. An
+The 'tar' program is used to create and manipulate 'tar' archives. An
"archive" is a single file which contains the contents of many files,
while still identifying the names of the files, their owner(s), and so
forth. (In addition, archives record access permissions, user and
group, size in bytes, and data modification time. Some archives also
record the file names in each archived directory, as well as other file
-and directory information.) You can use `tar' to "create" a new
-archive in a specified directory.
+and directory information.) You can use 'tar' to "create" a new archive
+in a specified directory.
The files inside an archive are called "members". Within this
manual, we use the term "file" to refer only to files accessible in the
-normal ways (by `ls', `cat', and so forth), and the term "member" to
+normal ways (by 'ls', 'cat', and so forth), and the term "member" to
refer only to the members of an archive. Similarly, a "file name" is
the name of a file, as it resides in the file system, and a "member
name" is the name of an archive member within the archive.
The term "extraction" refers to the process of copying an archive
member (or multiple members) into a file in the file system. Extracting
all the members of an archive is often called "extracting the archive".
-The term "unpack" can also be used to refer to the extraction of many
-or all the members of an archive. Extracting an archive does not
-destroy the archive's structure, just as creating an archive does not
-destroy the copies of the files that exist outside of the archive. You
-may also "list" the members in a given archive (this is often thought
-of as "printing" them to the standard output, or the command line), or
-"append" members to a pre-existing archive. All of these operations
-can be performed using `tar'.
+The term "unpack" can also be used to refer to the extraction of many or
+all the members of an archive. Extracting an archive does not destroy
+the archive's structure, just as creating an archive does not destroy
+the copies of the files that exist outside of the archive. You may also
+"list" the members in a given archive (this is often thought of as
+"printing" them to the standard output, or the command line), or
+"append" members to a pre-existing archive. All of these operations can
+be performed using 'tar'.
\1f
File: tar.info, Node: What tar Does, Next: Naming tar Archives, Prev: Definitions, Up: Introduction
-1.3 What `tar' Does
+1.3 What 'tar' Does
===================
-The `tar' program provides the ability to create `tar' archives, as
-well as various other kinds of manipulation. For example, you can use
-`tar' on previously created archives to extract files, to store
-additional files, or to update or list files which were already stored.
+The 'tar' program provides the ability to create 'tar' archives, as well
+as various other kinds of manipulation. For example, you can use 'tar'
+on previously created archives to extract files, to store additional
+files, or to update or list files which were already stored.
- Initially, `tar' archives were used to store files conveniently on
-magnetic tape. The name `tar' comes from this use; it stands for
-`t'ape `ar'chiver. Despite the utility's name, `tar' can direct its
-output to available devices, files, or other programs (using pipes).
-`tar' may even access remote devices or files (as archives).
+ Initially, 'tar' archives were used to store files conveniently on
+magnetic tape. The name 'tar' comes from this use; it stands for 't'ape
+'ar'chiver. Despite the utility's name, 'tar' can direct its output to
+available devices, files, or other programs (using pipes). 'tar' may
+even access remote devices or files (as archives).
- You can use `tar' archives in many ways. We want to stress a few of
+ You can use 'tar' archives in many ways. We want to stress a few of
them: storage, backup, and transportation.
Storage
- Often, `tar' archives are used to store related files for
+ Often, 'tar' archives are used to store related files for
convenient file transfer over a network. For example, the GNU
- Project distributes its software bundled into `tar' archives, so
+ Project distributes its software bundled into 'tar' archives, so
that all the files relating to a particular program (or set of
related programs) can be transferred as a single unit.
A magnetic tape can store several files in sequence. However, the
tape has no names for these files; it only knows their relative
position on the tape. One way to store several files on one tape
- and retain their names is by creating a `tar' archive. Even when
+ and retain their names is by creating a 'tar' archive. Even when
the basic transfer mechanism can keep track of names, as FTP can,
the nuisance of handling multiple files, directories, and multiple
- links makes `tar' archives useful.
+ links makes 'tar' archives useful.
Archive files are also used for long-term storage. You can think
- of this as transportation from the present into the future. (It
- is a science-fiction idiom that you can move through time as well
- as in space; the idea here is that `tar' can be used to move
- archives in all dimensions, even time!)
+ of this as transportation from the present into the future. (It is
+ a science-fiction idiom that you can move through time as well as
+ in space; the idea here is that 'tar' can be used to move archives
+ in all dimensions, even time!)
Backup
- Because the archive created by `tar' is capable of preserving file
- information and directory structure, `tar' is commonly used for
+ Because the archive created by 'tar' is capable of preserving file
+ information and directory structure, 'tar' is commonly used for
performing full and incremental backups of disks. A backup puts a
collection of files (possibly pertaining to many users and
projects) together on a disk or a tape. This guards against
accidental destruction of the information in those files. GNU
- `tar' has special features that allow it to be used to make
+ 'tar' has special features that allow it to be used to make
incremental and full dumps of all the files in a file system.
Transportation
\1f
File: tar.info, Node: Naming tar Archives, Next: Authors, Prev: What tar Does, Up: Introduction
-1.4 How `tar' Archives are Named
+1.4 How 'tar' Archives are Named
================================
-Conventionally, `tar' archives are given names ending with `.tar'.
-This is not necessary for `tar' to operate properly, but this manual
-follows that convention in order to accustom readers to it and to make
-examples more clear.
+Conventionally, 'tar' archives are given names ending with '.tar'. This
+is not necessary for 'tar' to operate properly, but this manual follows
+that convention in order to accustom readers to it and to make examples
+more clear.
- Often, people refer to `tar' archives as "`tar' files," and archive
-members as "files" or "entries". For people familiar with the
-operation of `tar', this causes no difficulty. However, in this
-manual, we consistently refer to "archives" and "archive members" to
-make learning to use `tar' easier for novice users.
+ Often, people refer to 'tar' archives as "'tar' files," and archive
+members as "files" or "entries". For people familiar with the operation
+of 'tar', this causes no difficulty. However, in this manual, we
+consistently refer to "archives" and "archive members" to make learning
+to use 'tar' easier for novice users.
\1f
File: tar.info, Node: Authors, Next: Reports, Prev: Naming tar Archives, Up: Introduction
-1.5 GNU `tar' Authors
+1.5 GNU 'tar' Authors
=====================
-GNU `tar' was originally written by John Gilmore, and modified by many
+GNU 'tar' was originally written by John Gilmore, and modified by many
people. The GNU enhancements were written by Jay Fenlason, then Joy
Kendall, and the whole package has been further maintained by Thomas
Bushnell, n/BSG, Franc,ois Pinard, Paul Eggert, and finally Sergey
Poznyakoff with the help of numerous and kind users.
- We wish to stress that `tar' is a collective work, and owes much to
+ We wish to stress that 'tar' is a collective work, and owes much to
all those people who reported problems, offered solutions and other
insights, or shared their thoughts and suggestions. An impressive, yet
-partial list of those contributors can be found in the `THANKS' file
-from the GNU `tar' distribution.
+partial list of those contributors can be found in the 'THANKS' file
+from the GNU 'tar' distribution.
- Jay Fenlason put together a draft of a GNU `tar' manual, borrowing
+ Jay Fenlason put together a draft of a GNU 'tar' manual, borrowing
notes from the original man page from John Gilmore. This was withdrawn
in version 1.11. Thomas Bushnell, n/BSG and Amy Gorin worked on a
-tutorial and manual for GNU `tar'. Franc,ois Pinard put version 1.11.8
+tutorial and manual for GNU 'tar'. Franc,ois Pinard put version 1.11.8
of the manual together by taking information from all these sources and
merging them. Melissa Weisshaus finally edited and redesigned the book
-to create version 1.12. The book for versions from 1.14 up to 1.28
-were edited by the current maintainer, Sergey Poznyakoff.
+to create version 1.12. The book for versions from 1.14 up to 1.29 were
+edited by the current maintainer, Sergey Poznyakoff.
For version 1.12, Daniel Hagerty contributed a great deal of
technical consulting. In particular, he is the primary author of *note
Backups::.
- In July, 2003 GNU `tar' was put on CVS at savannah.gnu.org (see
-`http://savannah.gnu.org/projects/tar'), and active development and
-maintenance work has started again. Currently GNU `tar' is being
+ In July, 2003 GNU 'tar' was put on CVS at savannah.gnu.org (see
+<http://savannah.gnu.org/projects/tar>), and active development and
+maintenance work has started again. Currently GNU 'tar' is being
maintained by Paul Eggert, Sergey Poznyakoff and Jeff Bailey.
Support for POSIX archives was added by Sergey Poznyakoff.
=================================
If you find problems or have suggestions about this program or manual,
-please report them to `bug-tar@gnu.org'.
+please report them to 'bug-tar@gnu.org'.
When reporting a bug, please be sure to include as much detail as
possible, in order to reproduce it.
\1f
File: tar.info, Node: Tutorial, Next: tar invocation, Prev: Introduction, Up: Top
-2 Tutorial Introduction to `tar'
+2 Tutorial Introduction to 'tar'
********************************
-This chapter guides you through some basic examples of three `tar'
-operations: `--create', `--list', and `--extract'. If you already know
-how to use some other version of `tar', then you may not need to read
+This chapter guides you through some basic examples of three 'tar'
+operations: '--create', '--list', and '--extract'. If you already know
+how to use some other version of 'tar', then you may not need to read
this chapter. This chapter omits most complicated details about how
-`tar' works.
+'tar' works.
* Menu:
* assumptions::
* stylistic conventions::
-* basic tar options:: Basic `tar' Operations and Options
+* basic tar options:: Basic 'tar' Operations and Options
* frequent operations::
* Two Frequent Options::
* create:: How to Create Archives
2.1 Assumptions this Tutorial Makes
===================================
-This chapter is paced to allow beginners to learn about `tar' slowly.
+This chapter is paced to allow beginners to learn about 'tar' slowly.
At the same time, we will try to cover all the basic aspects of these
three operations. In order to accomplish both of these tasks, we have
made certain assumptions about your knowledge before reading this
some basic understanding of directory structure and how files are
named according to which directory they are in. You should
understand concepts such as standard output and standard input,
- what various definitions of the term `argument' mean, and the
+ what various definitions of the term 'argument' mean, and the
differences between relative and absolute file names.
* This manual assumes that you are working from your own home
directory (unless we state otherwise). In this tutorial, you will
- create a directory to practice `tar' commands in. When we show
+ create a directory to practice 'tar' commands in. When we show
file names, we will assume that those names are relative to your
home directory. For example, my home directory is
- `/home/fsf/melissa'. All of my examples are in a subdirectory of
+ '/home/fsf/melissa'. All of my examples are in a subdirectory of
the directory named by that file name; the subdirectory is called
- `practice'.
+ 'practice'.
* In general, we show examples of archives which exist on (or can be
written to, or worked with from) a directory on a hard disk. In
- most cases, you could write those archives to, or work with them
- on any other device, such as a tape drive. However, some of the
- later examples in the tutorial and next chapter will not work on
- tape drives. Additionally, working with tapes is much more
- complicated than working with hard disks. For these reasons, the
- tutorial does not cover working with tape drives. *Note Media::,
- for complete information on using `tar' archives with tape drives.
-
+ most cases, you could write those archives to, or work with them on
+ any other device, such as a tape drive. However, some of the later
+ examples in the tutorial and next chapter will not work on tape
+ drives. Additionally, working with tapes is much more complicated
+ than working with hard disks. For these reasons, the tutorial does
+ not cover working with tape drives. *Note Media::, for complete
+ information on using 'tar' archives with tape drives.
\1f
File: tar.info, Node: stylistic conventions, Next: basic tar options, Prev: assumptions, Up: Tutorial
2.2 Stylistic Conventions
=========================
-In the examples, `$' represents a typical shell prompt. It precedes
-lines you should type; to make this more clear, those lines are shown
-in `this font', as opposed to lines which represent the computer's
-response; those lines are shown in `this font', or sometimes `like
+In the examples, '$' represents a typical shell prompt. It precedes
+lines you should type; to make this more clear, those lines are shown in
+'this font', as opposed to lines which represent the computer's
+response; those lines are shown in 'this font', or sometimes 'like
this'.
\1f
File: tar.info, Node: basic tar options, Next: frequent operations, Prev: stylistic conventions, Up: Tutorial
-2.3 Basic `tar' Operations and Options
+2.3 Basic 'tar' Operations and Options
======================================
-`tar' can take a wide variety of arguments which specify and define the
-actions it will have on the particular set of files or the archive.
-The main types of arguments to `tar' fall into one of two classes:
+'tar' can take a wide variety of arguments which specify and define the
+actions it will have on the particular set of files or the archive. The
+main types of arguments to 'tar' fall into one of two classes:
operations, and options.
Some arguments fall into a class called "operations"; exactly one of
-these is both allowed and required for any instance of using `tar'; you
+these is both allowed and required for any instance of using 'tar'; you
may _not_ specify more than one. People sometimes speak of "operating
modes". You are in a particular operating mode when you have specified
the operation which specifies it; there are eight operations in total,
The other arguments fall into the class known as "options". You are
not required to specify any options, and you are allowed to specify more
-than one at a time (depending on the way you are using `tar' at that
+than one at a time (depending on the way you are using 'tar' at that
time). Some options are used so frequently, and are so useful for
helping you type commands more carefully that they are effectively
"required". We will discuss them in this chapter.
- You can write most of the `tar' operations and options in any of
+ You can write most of the 'tar' operations and options in any of
three forms: long (mnemonic) form, short form, and old style. Some of
the operations and options have no short or "old" forms; however, the
operations and options which we will cover in this tutorial have
corresponding abbreviations. We will indicate those abbreviations
appropriately to get you used to seeing them. Note, that the "old
-style" option forms exist in GNU `tar' for compatibility with Unix
-`tar'. In this book we present a full discussion of this way of
-writing options and operations (*note Old Options::), and we discuss
-the other two styles of writing options (*Note Long Options::, and
-*note Short Options::).
+style" option forms exist in GNU 'tar' for compatibility with Unix
+'tar'. In this book we present a full discussion of this way of writing
+options and operations (*note Old Options::), and we discuss the other
+two styles of writing options (*Note Long Options::, and *note Short
+Options::).
In the examples and in the text of this tutorial, we usually use the
long forms of operations and options; but the "short" forms produce the
-same result and can make typing long `tar' commands easier. For
+same result and can make typing long 'tar' commands easier. For
example, instead of typing
tar --create --verbose --file=afiles.tar apple angst aspic
discussions in the text, when we name an option by its long form, we
also give the corresponding short option in parentheses.
- The term, "option", can be confusing at times, since "operations"
-are often lumped in with the actual, _optional_ "options" in certain
-general class statements. For example, we just talked about "short and
-long forms of options and operations". However, experienced `tar'
-users often refer to these by shorthand terms such as, "short and long
+ The term, "option", can be confusing at times, since "operations" are
+often lumped in with the actual, _optional_ "options" in certain general
+class statements. For example, we just talked about "short and long
+forms of options and operations". However, experienced 'tar' users
+often refer to these by shorthand terms such as, "short and long
options". This term assumes that the "operations" are included, also.
Context will help you determine which definition of "options" to use.
Similarly, the term "command" can be confusing, as it is often used
-in two different ways. People sometimes refer to `tar' "commands". A
-`tar' "command" is the entire command line of user input which tells
-`tar' what to do -- including the operation, options, and any arguments
+in two different ways. People sometimes refer to 'tar' "commands". A
+'tar' "command" is the entire command line of user input which tells
+'tar' what to do -- including the operation, options, and any arguments
(file names, pipes, other commands, etc.). However, you will also
-sometimes hear the term "the `tar' command". When the word "command"
-is used specifically like this, a person is usually referring to the
-`tar' _operation_, not the whole line. Again, use context to figure
-out which of the meanings the speaker intends.
+sometimes hear the term "the 'tar' command". When the word "command" is
+used specifically like this, a person is usually referring to the 'tar'
+_operation_, not the whole line. Again, use context to figure out which
+of the meanings the speaker intends.
\1f
File: tar.info, Node: frequent operations, Next: Two Frequent Options, Prev: basic tar options, Up: Tutorial
this chapter will cover how to use these operations in detail. We will
present the rest of the operations in the next chapter.
-`--create'
-`-c'
- Create a new `tar' archive.
-
-`--list'
-`-t'
+'--create'
+'-c'
+ Create a new 'tar' archive.
+'--list'
+'-t'
List the contents of an archive.
-
-`--extract'
-`-x'
+'--extract'
+'-x'
Extract one or more members from an archive.
\1f
2.5 Two Frequently Used Options
===============================
-To understand how to run `tar' in the three operating modes listed
+To understand how to run 'tar' in the three operating modes listed
previously, you also need to understand how to use two of the options to
-`tar': `--file' (which takes an archive file as an argument) and
-`--verbose'. (You are usually not _required_ to specify either of
-these options when you run `tar', but they can be very useful in making
-things more clear and helping you avoid errors.)
+'tar': '--file' (which takes an archive file as an argument) and
+'--verbose'. (You are usually not _required_ to specify either of these
+options when you run 'tar', but they can be very useful in making things
+more clear and helping you avoid errors.)
* Menu:
\1f
File: tar.info, Node: file tutorial, Next: verbose tutorial, Up: Two Frequent Options
-The `--file' Option
+The '--file' Option
-------------------
-`--file=ARCHIVE-NAME'
-`-f ARCHIVE-NAME'
+'--file=ARCHIVE-NAME'
+'-f ARCHIVE-NAME'
Specify the name of an archive file.
- You can specify an argument for the `--file=ARCHIVE-NAME' (`-f
-ARCHIVE-NAME') option whenever you use `tar'; this option determines
-the name of the archive file that `tar' will work on.
+ You can specify an argument for the '--file=ARCHIVE-NAME' ('-f
+ARCHIVE-NAME') option whenever you use 'tar'; this option determines the
+name of the archive file that 'tar' will work on.
- If you don't specify this argument, then `tar' will examine the
-environment variable `TAPE'. If it is set, its value will be used as
-the archive name. Otherwise, `tar' will use the default archive,
-determined at compile time. Usually it is standard output or some
+ If you don't specify this argument, then 'tar' will examine the
+environment variable 'TAPE'. If it is set, its value will be used as
+the archive name. Otherwise, 'tar' will use the default archive,
+determined at compile time. Usually it is standard output or some
physical tape drive attached to your machine (you can verify what the
-default is by running `tar --show-defaults', *note defaults::). If
+default is by running 'tar --show-defaults', *note defaults::). If
there is no tape drive attached, or the default is not meaningful, then
-`tar' will print an error message. The error message might look
-roughly like one of the following:
+'tar' will print an error message. The error message might look roughly
+like one of the following:
tar: can't open /dev/rmt8 : No such device or address
tar: can't open /dev/rsmt0 : I/O error
To avoid confusion, we recommend that you always specify an archive file
-name by using `--file=ARCHIVE-NAME' (`-f ARCHIVE-NAME') when writing
-your `tar' commands. For more information on using the
-`--file=ARCHIVE-NAME' (`-f ARCHIVE-NAME') option, see *note file::.
+name by using '--file=ARCHIVE-NAME' ('-f ARCHIVE-NAME') when writing
+your 'tar' commands. For more information on using the
+'--file=ARCHIVE-NAME' ('-f ARCHIVE-NAME') option, see *note file::.
\1f
File: tar.info, Node: verbose tutorial, Next: help tutorial, Prev: file tutorial, Up: Two Frequent Options
-The `--verbose' Option
+The '--verbose' Option
----------------------
-`--verbose'
-`-v'
- Show the files being worked on as `tar' is running.
+'--verbose'
+'-v'
+ Show the files being worked on as 'tar' is running.
- `--verbose' (`-v') shows details about the results of running `tar'.
+ '--verbose' ('-v') shows details about the results of running 'tar'.
This can be especially useful when the results might not be obvious.
-For example, if you want to see the progress of `tar' as it writes
-files into the archive, you can use the `--verbose' option. In the
-beginning, you may find it useful to use `--verbose' at all times; when
-you are more accustomed to `tar', you will likely want to use it at
-certain times but not at others. We will use `--verbose' at times to
-help make something clear, and we will give many examples both using
-and not using `--verbose' to show the differences.
-
- Each instance of `--verbose' on the command line increases the
+For example, if you want to see the progress of 'tar' as it writes files
+into the archive, you can use the '--verbose' option. In the beginning,
+you may find it useful to use '--verbose' at all times; when you are
+more accustomed to 'tar', you will likely want to use it at certain
+times but not at others. We will use '--verbose' at times to help make
+something clear, and we will give many examples both using and not using
+'--verbose' to show the differences.
+
+ Each instance of '--verbose' on the command line increases the
verbosity level by one, so if you need more details on the output,
specify it twice.
- When reading archives (`--list', `--extract', `--diff'), `tar' by
+ When reading archives ('--list', '--extract', '--diff'), 'tar' by
default prints only the names of the members being extracted. Using
-`--verbose' will show a full, `ls' style member listing.
+'--verbose' will show a full, 'ls' style member listing.
- In contrast, when writing archives (`--create', `--append',
-`--update'), `tar' does not print file names by default. So, a single
-`--verbose' option shows the file names being added to the archive,
-while two `--verbose' options enable the full listing.
+ In contrast, when writing archives ('--create', '--append',
+'--update'), 'tar' does not print file names by default. So, a single
+'--verbose' option shows the file names being added to the archive,
+while two '--verbose' options enable the full listing.
For example, to create an archive in verbose mode:
Note that you must double the hyphens properly each time.
Later in the tutorial, we will give examples using
-`--verbose --verbose'.
+'--verbose --verbose'.
The full output consists of six fields:
- * File type and permissions in symbolic form. These are displayed
- in the same format as the first column of `ls -l' output (*note
+ * File type and permissions in symbolic form. These are displayed in
+ the same format as the first column of 'ls -l' output (*note
format=verbose: (fileutils)What information is listed.).
- * Owner name and group separated by a slash character. If these
- data are not available (for example, when listing a `v7' format
+ * Owner name and group separated by a slash character. If these data
+ are not available (for example, when listing a 'v7' format
archive), numeric ID values are printed instead.
* Size of the file, in bytes.
Depending on the file type, the name can be followed by some
additional information, described in the following table:
- `-> LINK-NAME'
+ '-> LINK-NAME'
The file or archive member is a "symbolic link" and LINK-NAME
is the name of file it links to.
- `link to LINK-NAME'
+ 'link to LINK-NAME'
The file or archive member is a "hard link" and LINK-NAME is
the name of file it links to.
- `--Long Link--'
+ '--Long Link--'
The archive member is an old GNU format long link. You will
normally not encounter this.
- `--Long Name--'
+ '--Long Name--'
The archive member is an old GNU format long name. You will
normally not encounter this.
- `--Volume Header--'
+ '--Volume Header--'
The archive member is a GNU "volume header" (*note Tape
Files::).
- `--Continued at byte N--'
+ '--Continued at byte N--'
Encountered only at the beginning of a multi-volume archive
(*note Using Multiple Tapes::). This archive member is a
- continuation from the previous volume. The number N gives the
+ continuation from the previous volume. The number N gives the
offset where the original file was split.
- `unknown file type C'
- An archive member of unknown type. C is the type character
+ 'unknown file type C'
+ An archive member of unknown type. C is the type character
from the archive header. If you encounter such a message, it
means that either your archive contains proprietary member
- types GNU `tar' is not able to handle, or the archive is
+ types GNU 'tar' is not able to handle, or the archive is
corrupted.
-
For example, here is an archive listing containing most of the
special suffixes explained above:
\1f
File: tar.info, Node: help tutorial, Prev: verbose tutorial, Up: Two Frequent Options
-Getting Help: Using the `--help' Option
+Getting Help: Using the '--help' Option
---------------------------------------
-`--help'
- The `--help' option to `tar' prints out a very brief list of all
- operations and option available for the current version of `tar'
+'--help'
+
+ The '--help' option to 'tar' prints out a very brief list of all
+ operations and option available for the current version of 'tar'
available on your system.
\1f
2.6 How to Create Archives
==========================
- _(This message will disappear, once this node revised.)_
-
-One of the basic operations of `tar' is `--create' (`-c'), which you
-use to create a `tar' archive. We will explain `--create' first
-because, in order to learn about the other operations, you will find it
-useful to have an archive available to practice on.
+One of the basic operations of 'tar' is '--create' ('-c'), which you use
+to create a 'tar' archive. We will explain '--create' first because, in
+order to learn about the other operations, you will find it useful to
+have an archive available to practice on.
To make this easier, in this section you will first create a
directory containing three files. Then, we will show you how to create
directory and the files you will create: some of those files may be
other directories and other archives.
- The three files you will archive in this example are called `blues',
-`folk', and `jazz'. The archive is called `collection.tar'.
+ The three files you will archive in this example are called 'blues',
+'folk', and 'jazz'. The archive is called 'collection.tar'.
- This section will proceed slowly, detailing how to use `--create' in
-`verbose' mode, and showing examples using both short and long forms.
-In the rest of the tutorial, and in the examples in the next chapter,
-we will proceed at a slightly quicker pace. This section moves more
-slowly to allow beginning users to understand how `tar' works.
+ This section will proceed slowly, detailing how to use '--create' in
+'verbose' mode, and showing examples using both short and long forms.
+In the rest of the tutorial, and in the examples in the next chapter, we
+will proceed at a slightly quicker pace. This section moves more slowly
+to allow beginning users to understand how 'tar' works.
* Menu:
-------------------------------------------------
To follow along with this and future examples, create a new directory
-called `practice' containing files called `blues', `folk' and `jazz'.
+called 'practice' containing files called 'blues', 'folk' and 'jazz'.
The files can contain any information you like: ideally, they should
contain information which relates to their names, and be of different
-lengths. Our examples assume that `practice' is a subdirectory of your
+lengths. Our examples assume that 'practice' is a subdirectory of your
home directory.
- Now `cd' to the directory named `practice'; `practice' is now your
+ Now 'cd' to the directory named 'practice'; 'practice' is now your
"working directory". (_Please note_: Although the full file name of
-this directory is `/HOMEDIR/practice', in our examples we will refer to
-this directory as `practice'; the HOMEDIR is presumed.)
+this directory is '/HOMEDIR/practice', in our examples we will refer to
+this directory as 'practice'; the HOMEDIR is presumed.)
In general, you should check that the files to be archived exist
-where you think they do (in the working directory) by running `ls'.
+where you think they do (in the working directory) by running 'ls'.
Because you just created the directory and the files and have changed to
that directory, you probably don't need to do that this time.
It is very important to make sure there isn't already a file in the
working directory with the archive name you intend to use (in this case,
-`collection.tar'), or that you don't care about its contents. Whenever
-you use `create', `tar' will erase the current contents of the file
-named by `--file=ARCHIVE-NAME' (`-f ARCHIVE-NAME') if it exists. `tar'
+'collection.tar'), or that you don't care about its contents. Whenever
+you use 'create', 'tar' will erase the current contents of the file
+named by '--file=ARCHIVE-NAME' ('-f ARCHIVE-NAME') if it exists. 'tar'
will not tell you if you are about to overwrite an archive unless you
specify an option which does this (*note backup::, for the information
on how to do so). To add files to an existing archive, you need to use
-a different option, such as `--append' (`-r'); see *note append:: for
+a different option, such as '--append' ('-r'); see *note append:: for
information on how to do this.
\1f
2.6.2 Creating the Archive
--------------------------
-To place the files `blues', `folk', and `jazz' into an archive named
-`collection.tar', use the following command:
+To place the files 'blues', 'folk', and 'jazz' into an archive named
+'collection.tar', use the following command:
$ tar --create --file=collection.tar blues folk jazz
The order of the arguments is not very important, _when using long
-option forms_. You could also say:
+option forms_, however you should always remember to use option as the
+first argument to tar. For example, the following is wrong:
- $ tar blues --create folk --file=collection.tar jazz
+ $ tar blues -c folk -f collection.tar jazz
+ tar: -c: Invalid blocking factor
+ Try 'tar --help' or 'tar --usage' for more information.
+
+ The error message is produced because 'tar' always treats its first
+argument as an option (or cluster of options), even if it does not start
+with dash. This is "traditional" or "old option" style, called so
+because all implementations of 'tar' have used it since the very
+inception of the tar archiver in 1970s. This option style will be
+explained later (*note Old Options::), for now just remember to always
+place option as the first argument.
+
+ That being said, you could issue the following command:
+
+ $ tar --create folk blues --file=collection.tar jazz
However, you can see that this order is harder to understand; this is
why we will list the arguments in the order that makes the commands
easiest to understand (and we encourage you to do the same when you use
-`tar', to avoid errors).
+'tar', to avoid errors).
- Note that the sequence `--file=collection.tar' is considered to be
+ Note that the sequence '--file=collection.tar' is considered to be
_one_ argument. If you substituted any other string of characters for
-`collection.tar', then that string would become the name of the
-archive file you create.
+'collection.tar', then that string would become the name of the archive
+file you create.
The order of the options becomes more important when you begin to use
short forms. With short forms, if you type commands in the wrong order
into the habit of typing options in the order that makes inherent sense.
*Note short create::, for more information on this.
- In this example, you type the command as shown above: `--create' is
-the operation which creates the new archive (`collection.tar'), and
-`--file' is the option which lets you give it the name you chose. The
-files, `blues', `folk', and `jazz', are now members of the archive,
-`collection.tar' (they are "file name arguments" to the `--create'
+ In this example, you type the command as shown above: '--create' is
+the operation which creates the new archive ('collection.tar'), and
+'--file' is the option which lets you give it the name you chose. The
+files, 'blues', 'folk', and 'jazz', are now members of the archive,
+'collection.tar' (they are "file name arguments" to the '--create'
operation. *Note Choosing::, for the detailed discussion on these.)
-Now that they are in the archive, they are called _archive members_,
-not files. (*note members: Definitions.).
+Now that they are in the archive, they are called _archive members_, not
+files. (*note members: Definitions.).
When you create an archive, you _must_ specify which files you want
placed in the archive. If you do not specify any archive members, GNU
-`tar' will complain.
+'tar' will complain.
- If you now list the contents of the working directory (`ls'), you
+ If you now list the contents of the working directory ('ls'), you
will find the archive file listed as well as the files you saw
previously:
blues folk jazz collection.tar
-Creating the archive `collection.tar' did not destroy the copies of the
+Creating the archive 'collection.tar' did not destroy the copies of the
files in the directory.
- Keep in mind that if you don't indicate an operation, `tar' will not
-run and will prompt you for one. If you don't name any files, `tar'
+ Keep in mind that if you don't indicate an operation, 'tar' will not
+run and will prompt you for one. If you don't name any files, 'tar'
will complain. You must have write access to the working directory, or
else you will not be able to create an archive in that directory.
- _Caution_: Do not attempt to use `--create' (`-c') to add files to
-an existing archive; it will delete the archive and write a new one.
-Use `--append' (`-r') instead. *Note append::.
+ _Caution_: Do not attempt to use '--create' ('-c') to add files to an
+existing archive; it will delete the archive and write a new one. Use
+'--append' ('-r') instead. *Note append::.
\1f
File: tar.info, Node: create verbose, Next: short create, Prev: Creating the archive, Up: create
-2.6.3 Running `--create' with `--verbose'
+2.6.3 Running '--create' with '--verbose'
-----------------------------------------
-If you include the `--verbose' (`-v') option on the command line, `tar'
+If you include the '--verbose' ('-v') option on the command line, 'tar'
will list the files it is acting on as it is working. In verbose mode,
-the `create' example above would appear as:
+the 'create' example above would appear as:
$ tar --create --verbose --file=collection.tar blues folk jazz
blues
jazz
This example is just like the example we showed which did not use
-`--verbose', except that `tar' generated the remaining lines.
+'--verbose', except that 'tar' generated the remaining lines.
In the rest of the examples in this chapter, we will frequently use
-`verbose' mode so we can show actions or `tar' responses that you would
+'verbose' mode so we can show actions or 'tar' responses that you would
otherwise not see, and which are important for you to understand.
\1f
File: tar.info, Node: short create, Next: create dir, Prev: create verbose, Up: create
-2.6.4 Short Forms with `create'
+2.6.4 Short Forms with 'create'
-------------------------------
-As we said before, the `--create' (`-c') operation is one of the most
-basic uses of `tar', and you will use it countless times. Eventually,
-you will probably want to use abbreviated (or "short") forms of
-options. A full discussion of the three different forms that options
-can take appears in *note Styles::; for now, here is what the previous
-example (including the `--verbose' (`-v') option) looks like using
-short option forms:
+As we said before, the '--create' ('-c') operation is one of the most
+basic uses of 'tar', and you will use it countless times. Eventually,
+you will probably want to use abbreviated (or "short") forms of options.
+A full discussion of the three different forms that options can take
+appears in *note Styles::; for now, here is what the previous example
+(including the '--verbose' ('-v') option) looks like using short option
+forms:
$ tar -cvf collection.tar blues folk jazz
blues
$ tar -cfv collection.tar blues folk jazz
-In this case, `tar' will make an archive file called `v', containing
-the files `blues', `folk', and `jazz', because the `v' is the closest
-"file name" to the `-f' option, and is thus taken to be the chosen
-archive file name. `tar' will try to add a file called
-`collection.tar' to the `v' archive file; if the file `collection.tar'
-did not already exist, `tar' will report an error indicating that this
-file does not exist. If the file `collection.tar' does already exist
-(e.g., from a previous command you may have run), then `tar' will add
-this file to the archive. Because the `-v' option did not get
-registered, `tar' will not run under `verbose' mode, and will not
-report its progress.
+In this case, 'tar' will make an archive file called 'v', containing the
+files 'blues', 'folk', and 'jazz', because the 'v' is the closest "file
+name" to the '-f' option, and is thus taken to be the chosen archive
+file name. 'tar' will try to add a file called 'collection.tar' to the
+'v' archive file; if the file 'collection.tar' did not already exist,
+'tar' will report an error indicating that this file does not exist. If
+the file 'collection.tar' does already exist (e.g., from a previous
+command you may have run), then 'tar' will add this file to the archive.
+Because the '-v' option did not get registered, 'tar' will not run under
+'verbose' mode, and will not report its progress.
The end result is that you may be quite confused about what happened,
and possibly overwrite a file. To illustrate this further, we will show
This example,
- $ tar blues --create folk --file=collection.tar jazz
+ $ tar --create folk blues --file=collection.tar jazz
-is confusing as it is. When shown using short forms, however, it
-becomes much more so:
+is confusing as it is. It becomes even more so when using short forms:
- $ tar blues -c folk -f collection.tar jazz
+ $ tar -c folk blues -f collection.tar jazz
It would be very easy to put the wrong string of characters immediately
-following the `-f', but doing that could sacrifice valuable data.
+following the '-f', but doing that could sacrifice valuable data.
For this reason, we recommend that you pay very careful attention to
-the order of options and placement of file and archive names,
-especially when using short option forms. Not having the option name
-written out mnemonically can affect how well you remember which option
-does what, and therefore where different names have to be placed.
+the order of options and placement of file and archive names, especially
+when using short option forms. Not having the option name written out
+mnemonically can affect how well you remember which option does what,
+and therefore where different names have to be placed.
\1f
File: tar.info, Node: create dir, Prev: short create, Up: create
---------------------------
You can archive a directory by specifying its directory name as a file
-name argument to `tar'. The files in the directory will be archived
+name argument to 'tar'. The files in the directory will be archived
relative to the working directory, and the directory will be re-created
along with its contents when the archive is extracted.
$ cd ..
$
-This will put you into the directory which contains `practice', i.e.,
+This will put you into the directory which contains 'practice', i.e.,
your home directory. Once in the superior directory, you can specify
-the subdirectory, `practice', as a file name argument. To store
-`practice' in the new archive file `music.tar', type:
+the subdirectory, 'practice', as a file name argument. To store
+'practice' in the new archive file 'music.tar', type:
$ tar --create --verbose --file=music.tar practice
-`tar' should output:
+'tar' should output:
practice/
practice/blues
practice/collection.tar
Note that the archive thus created is not in the subdirectory
-`practice', but rather in the current working directory--the directory
-from which `tar' was invoked. Before trying to archive a directory
-from its superior directory, you should make sure you have write access
-to the superior directory itself, not only the directory you are trying
-archive with `tar'. For example, you will probably not be able to
-store your home directory in an archive by invoking `tar' from the root
-directory; *Note absolute::. (Note also that `collection.tar', the
-original archive file, has itself been archived. `tar' will accept any
+'practice', but rather in the current working directory--the directory
+from which 'tar' was invoked. Before trying to archive a directory from
+its superior directory, you should make sure you have write access to
+the superior directory itself, not only the directory you are trying
+archive with 'tar'. For example, you will probably not be able to store
+your home directory in an archive by invoking 'tar' from the root
+directory; *Note absolute::. (Note also that 'collection.tar', the
+original archive file, has itself been archived. 'tar' will accept any
file as a file to be archived, regardless of its content. When
-`music.tar' is extracted, the archive file `collection.tar' will be
+'music.tar' is extracted, the archive file 'collection.tar' will be
re-written into the file system).
- If you give `tar' a command such as
+ If you give 'tar' a command such as
$ tar --create --file=foo.tar .
-`tar' will report `tar: ./foo.tar is the archive; not dumped'. This
-happens because `tar' creates the archive `foo.tar' in the current
-directory before putting any files into it. Then, when `tar' attempts
-to add all the files in the directory `.' to the archive, it notices
-that the file `./foo.tar' is the same as the archive `foo.tar', and
-skips it. (It makes no sense to put an archive into itself.) GNU `tar'
+'tar' will report 'tar: ./foo.tar is the archive; not dumped'. This
+happens because 'tar' creates the archive 'foo.tar' in the current
+directory before putting any files into it. Then, when 'tar' attempts
+to add all the files in the directory '.' to the archive, it notices
+that the file './foo.tar' is the same as the archive 'foo.tar', and
+skips it. (It makes no sense to put an archive into itself.) GNU 'tar'
will continue in this case, and create the archive normally, except for
the exclusion of that one file. (_Please note:_ Other implementations
-of `tar' may not be so clever; they will enter an infinite loop when
+of 'tar' may not be so clever; they will enter an infinite loop when
this happens, so you should not depend on this behavior unless you are
-certain you are running GNU `tar'. In general, it is wise to always
+certain you are running GNU 'tar'. In general, it is wise to always
place the archive outside of the directory being dumped.)
\1f
========================
Frequently, you will find yourself wanting to determine exactly what a
-particular archive contains. You can use the `--list' (`-t') operation
-to get the member names as they currently appear in the archive, as
-well as various attributes of the files at the time they were archived.
-For example, you can examine the archive `collection.tar' that you
-created in the last section with the command,
+particular archive contains. You can use the '--list' ('-t') operation
+to get the member names as they currently appear in the archive, as well
+as various attributes of the files at the time they were archived. For
+example, assuming 'practice' is your working directory, you can examine
+the archive 'collection.tar' that you created in the last section with
+the command,
$ tar --list --file=collection.tar
-The output of `tar' would then be:
+The output of 'tar' would then be:
blues
folk
jazz
-The archive `bfiles.tar' would list as follows:
+Be sure to use a '--file=ARCHIVE-NAME' ('-f ARCHIVE-NAME') option just
+as with '--create' ('-c') to specify the name of the archive.
- ./birds
- baboon
- ./box
+ You can specify one or more individual member names as arguments when
+using 'list'. In this case, 'tar' will only list the names of members
+you identify. For example, 'tar --list --file=collection.tar folk'
+would only print 'folk':
-Be sure to use a `--file=ARCHIVE-NAME' (`-f ARCHIVE-NAME') option just
-as with `--create' (`-c') to specify the name of the archive.
+ $ tar --list --file=collection.tar folk
+ folk
- If you use the `--verbose' (`-v') option with `--list', then `tar'
-will print out a listing reminiscent of `ls -l', showing owner, file
-size, and so forth. This output is described in detail in *note
-verbose member listing::.
+ If you use the '--verbose' ('-v') option with '--list', then 'tar'
+will print out a listing reminiscent of 'ls -l', showing owner, file
+size, and so forth. This output is described in detail in *note verbose
+member listing::.
- If you had used `--verbose' (`-v') mode, the example above would
-look like:
+ If you had used '--verbose' ('-v') mode, the example above would look
+like:
$ tar --list --verbose --file=collection.tar folk
-rw-r--r-- myself/user 62 1990-05-23 10:55 folk
- It is important to notice that the output of `tar --list --verbose'
-does not necessarily match that produced by `tar --create --verbose'
-while creating the archive. It is because GNU `tar', unless told
-explicitly not to do so, removes some directory prefixes from file
-names before storing them in the archive (*Note absolute::, for more
-information). In other words, in verbose mode GNU `tar' shows "file
+ It is important to notice that the output of 'tar --list --verbose'
+does not necessarily match that produced by 'tar --create --verbose'
+while creating the archive. It is because GNU 'tar', unless told
+explicitly not to do so, removes some directory prefixes from file names
+before storing them in the archive (*Note absolute::, for more
+information). In other words, in verbose mode GNU 'tar' shows "file
names" when creating an archive and "member names" when listing it.
-Consider this example:
+Consider this example, run from your home directory:
- $ tar --create --verbose --file archive /etc/mail
+ $ tar --create --verbose --file practice.tar ~/practice
tar: Removing leading '/' from member names
- /etc/mail/
- /etc/mail/sendmail.cf
- /etc/mail/aliases
- $ tar --test --file archive
- etc/mail/
- etc/mail/sendmail.cf
- etc/mail/aliases
+ /home/myself/practice/
+ /home/myself/practice/blues
+ /home/myself/practice/folk
+ /home/myself/practice/jazz
+ /home/myself/practice/collection.tar
+ $ tar --test --file practice.tar
+ home/myself/practice/
+ home/myself/practice/blues
+ home/myself/practice/folk
+ home/myself/practice/jazz
+ home/myself/practice/collection.tar
This default behavior can sometimes be inconvenient. You can force
-GNU `tar' show member names when creating archive by supplying
-`--show-stored-names' option.
+GNU 'tar' show member names when creating archive by supplying
+'--show-stored-names' option.
-`--show-stored-names'
+'--show-stored-names'
Print member (as opposed to _file_) names when creating the
archive.
- You can specify one or more individual member names as arguments when
-using `list'. In this case, `tar' will only list the names of members
-you identify. For example, `tar --list --file=afiles.tar apple' would
-only print `apple'.
-
- Because `tar' preserves file names, these must be specified as they
-appear in the archive (i.e., relative to the directory from which the
-archive was created). Therefore, it is essential when specifying
-member names to `tar' that you give the exact member names. For
-example, `tar --list --file=bfiles.tar birds' would produce an error
-message something like `tar: birds: Not found in archive', because
-there is no member named `birds', only one named `./birds'. While the
-names `birds' and `./birds' name the same file, _member_ names by
-default are compared verbatim.
-
- However, `tar --list --file=bfiles.tar baboon' would respond with
-`baboon', because this exact member name is in the archive file
-`bfiles.tar'. If you are not sure of the exact file name, use
-"globbing patterns", for example:
-
- $ tar --list --file=bfiles.tar --wildcards '*b*'
-
-will list all members whose name contains `b'. *Note wildcards::, for
-a detailed discussion of globbing patterns and related `tar' command
-line options.
+ With this option, both commands produce the same output:
+
+ $ tar --create --verbose --show-stored-names \
+ --file practice.tar ~/practice
+ tar: Removing leading '/' from member names
+ home/myself/practice/
+ home/myself/practice/blues
+ home/myself/practice/folk
+ home/myself/practice/jazz
+ home/myself/practice/collection.tar
+ $ tar --test --file practice.tar
+ home/myself/practice/
+ home/myself/practice/blues
+ home/myself/practice/folk
+ home/myself/practice/jazz
+ home/myself/practice/collection.tar
+
+ Since 'tar' preserves file names, those you wish to list must be
+specified as they appear in the archive (i.e., relative to the directory
+from which the archive was created). Continuing the example above:
+
+ $ tar --list --file=practice.tar folk
+ tar: folk: Not found in archive
+ tar: Exiting with failure status due to previous errors
+
+ the error message is produced because there is no member named
+'folk', only one named 'home/myself/folk'.
+
+ If you are not sure of the exact file name, use "globbing patterns",
+for example:
+
+ $ tar --list --file=practice.tar --wildcards '*/folk'
+ home/myself/practice/folk
+
+*Note wildcards::, for a detailed discussion of globbing patterns and
+related 'tar' command line options.
* Menu:
------------------------------------------
To get information about the contents of an archived directory, use the
-directory name as a file name argument in conjunction with `--list'
-(`-t'). To find out file attributes, include the `--verbose' (`-v')
+directory name as a file name argument in conjunction with '--list'
+('-t'). To find out file attributes, include the '--verbose' ('-v')
option.
- For example, to find out about files in the directory `practice', in
-the archive file `music.tar', type:
+ For example, to find out about files in the directory 'practice', in
+the archive file 'music.tar', type:
$ tar --list --verbose --file=music.tar practice
- `tar' responds:
+ 'tar' responds:
drwxrwxrwx myself/user 0 1990-05-31 21:49 practice/
-rw-r--r-- myself/user 42 1990-05-21 13:29 practice/blues
-rw-r--r-- myself/user 40 1990-05-21 13:30 practice/jazz
-rw-r--r-- myself/user 10240 1990-05-31 21:49 practice/collection.tar
- When you use a directory name as a file name argument, `tar' acts on
+ When you use a directory name as a file name argument, 'tar' acts on
all the files (including sub-directories) in that directory.
\1f
Creating an archive is only half the job--there is no point in storing
files in an archive if you can't retrieve them. The act of retrieving
members from an archive so they can be used and manipulated as
-unarchived files again is called "extraction". To extract files from
-an archive, use the `--extract' (`--get' or `-x') operation. As with
-`--create', specify the name of the archive with `--file' (`-f')
-option. Extracting an archive does not modify the archive in any way;
-you can extract it multiple times if you want or need to.
+unarchived files again is called "extraction". To extract files from an
+archive, use the '--extract' ('--get' or '-x') operation. As with
+'--create', specify the name of the archive with '--file' ('-f') option.
+Extracting an archive does not modify the archive in any way; you can
+extract it multiple times if you want or need to.
- Using `--extract', you can extract an entire archive, or specific
+ Using '--extract', you can extract an entire archive, or specific
files. The files can be directories containing other files, or not. As
-with `--create' (`-c') and `--list' (`-t'), you may use the short or the
+with '--create' ('-c') and '--list' ('-t'), you may use the short or the
long form of the operation without affecting the performance.
* Menu:
produces this:
- -rw-r--r-- me/user 28 1996-10-18 16:31 jazz
- -rw-r--r-- me/user 21 1996-09-23 16:44 blues
- -rw-r--r-- me/user 20 1996-09-23 16:44 folk
+ -rw-r--r-- myself/user 28 1996-10-18 16:31 jazz
+ -rw-r--r-- myself/user 21 1996-09-23 16:44 blues
+ -rw-r--r-- myself/user 20 1996-09-23 16:44 folk
\1f
File: tar.info, Node: extracting files, Next: extract dir, Prev: extracting archives, Up: extract
-------------------------------
To extract specific archive members, give their exact member names as
-arguments, as printed by `--list' (`-t'). If you had mistakenly
-deleted one of the files you had placed in the archive `collection.tar'
-earlier (say, `blues'), you can extract it from the archive without
-changing the archive's structure. Its contents will be identical to
-the original file `blues' that you deleted.
-
- First, make sure you are in the `practice' directory, and list the
-files in the directory. Now, delete the file, `blues', and list the
+arguments, as printed by '--list' ('-t'). If you had mistakenly deleted
+one of the files you had placed in the archive 'collection.tar' earlier
+(say, 'blues'), you can extract it from the archive without changing the
+archive's structure. Its contents will be identical to the original
+file 'blues' that you deleted.
+
+ First, make sure you are in the 'practice' directory, and list the
+files in the directory. Now, delete the file, 'blues', and list the
files in the directory again.
- You can now extract the member `blues' from the archive file
-`collection.tar' like this:
+ You can now extract the member 'blues' from the archive file
+'collection.tar' like this:
$ tar --extract --file=collection.tar blues
If you list the files in the directory again, you will see that the file
-`blues' has been restored, with its original permissions, data
+'blues' has been restored, with its original permissions, data
modification times, and owner.(1) (These parameters will be identical
to those which the file had when you originally placed it in the
-archive; any changes you may have made before deleting the file from
-the file system, however, will _not_ have been made to the archive
-member.) The archive file, `collection.tar', is the same as it was
-before you extracted `blues'. You can confirm this by running `tar'
-with `--list' (`-t').
+archive; any changes you may have made before deleting the file from the
+file system, however, will _not_ have been made to the archive member.)
+The archive file, 'collection.tar', is the same as it was before you
+extracted 'blues'. You can confirm this by running 'tar' with '--list'
+('-t').
Remember that as with other operations, specifying the exact member
-name is important. `tar --extract --file=bfiles.tar birds' will fail,
-because there is no member named `birds'. To extract the member named
-`./birds', you must specify `tar --extract --file=bfiles.tar ./birds'.
-If you don't remember the exact member names, use `--list' (`-t') option
-(*note list::). You can also extract those members that match a
-specific "globbing pattern". For example, to extract from `bfiles.tar'
-all files that begin with `b', no matter their directory prefix, you
-could type:
-
- $ tar -x -f bfiles.tar --wildcards --no-anchored 'b*'
-
-Here, `--wildcards' instructs `tar' to treat command line arguments as
-globbing patterns and `--no-anchored' informs it that the patterns
-apply to member names after any `/' delimiter. The use of globbing
-patterns is discussed in detail in *Note wildcards::.
+name is important (*Note failing commands::, for more examples).
You can extract a file to standard output by combining the above
-options with the `--to-stdout' (`-O') option (*note Writing to Standard
+options with the '--to-stdout' ('-O') option (*note Writing to Standard
Output::).
- If you give the `--verbose' option, then `--extract' will print the
+ If you give the '--verbose' option, then '--extract' will print the
names of the archive members as it extracts them.
---------- Footnotes ----------
modification times are always restored, in most cases, one has to be
root for restoring the owner, and use a special option for restoring
permissions. Here, it just happens that the restoring user is also the
-owner of the archived members, and that the current `umask' is
+owner of the archived members, and that the current 'umask' is
compatible with original permissions.
\1f
the working directory, then files in the extracted directory will be
placed into the directory of the same name. Likewise, if there are
files in the pre-existing directory with the same names as the members
-which you extract, the files from the extracted archive will replace
-the files already in the working directory (and possible
-subdirectories). This will happen regardless of whether or not the
-files in the working directory were more recent than those extracted
-(there exist, however, special options that alter this behavior *note
-Writing::).
+which you extract, the files from the extracted archive will replace the
+files already in the working directory (and possible subdirectories).
+This will happen regardless of whether or not the files in the working
+directory were more recent than those extracted (there exist, however,
+special options that alter this behavior *note Writing::).
However, if a file was stored with a directory name as part of its
-file name, and that directory does not exist under the working
-directory when the file is extracted, `tar' will create the directory.
-
- We can demonstrate how to use `--extract' to extract a directory
-file with an example. Change to the `practice' directory if you
-weren't there, and remove the files `folk' and `jazz'. Then, go back
-to the parent directory and extract the archive `music.tar'. You may
-either extract the entire archive, or you may extract only the files
-you just deleted. To extract the entire archive, don't give any file
-names as arguments after the archive name `music.tar'. To extract only
-the files you deleted, use the following command:
+file name, and that directory does not exist under the working directory
+when the file is extracted, 'tar' will create the directory.
+
+ We can demonstrate how to use '--extract' to extract a directory file
+with an example. Change to the 'practice' directory if you weren't
+there, and remove the files 'folk' and 'jazz'. Then, go back to the
+parent directory and extract the archive 'music.tar'. You may either
+extract the entire archive, or you may extract only the files you just
+deleted. To extract the entire archive, don't give any file names as
+arguments after the archive name 'music.tar'. To extract only the files
+you deleted, use the following command:
$ tar -xvf music.tar practice/folk practice/jazz
practice/folk
practice/jazz
-If you were to specify two `--verbose' (`-v') options, `tar' would have
-displayed more detail about the extracted files, as shown in the
-example below:
+If you were to specify two '--verbose' ('-v') options, 'tar' would have
+displayed more detail about the extracted files, as shown in the example
+below:
$ tar -xvvf music.tar practice/folk practice/jazz
-rw-r--r-- me/user 28 1996-10-18 16:31 practice/jazz
-rw-r--r-- me/user 20 1996-09-23 16:44 practice/folk
-Because you created the directory with `practice' as part of the file
-names of each of the files by archiving the `practice' directory as
-`practice', you must give `practice' as part of the file names when you
+Because you created the directory with 'practice' as part of the file
+names of each of the files by archiving the 'practice' directory as
+'practice', you must give 'practice' as part of the file names when you
extract those files from the archive.
\1f
Extracting files from archives can overwrite files that already exist.
If you receive an archive from an untrusted source, you should make a
-new directory and extract into that directory, so that you don't have
-to worry about the extraction overwriting one of your existing files.
-For example, if `untrusted.tar' came from somewhere else on the
-Internet, and you don't necessarily trust its contents, you can extract
-it as follows:
+new directory and extract into that directory, so that you don't have to
+worry about the extraction overwriting one of your existing files. For
+example, if 'untrusted.tar' came from somewhere else on the Internet,
+and you don't necessarily trust its contents, you can extract it as
+follows:
$ mkdir newdir
$ cd newdir
$ tar -xvf ../untrusted.tar
It is also a good practice to examine contents of the archive before
-extracting it, using `--list' (`-t') option, possibly combined with
-`--verbose' (`-v').
+extracting it, using '--list' ('-t') option, possibly combined with
+'--verbose' ('-v').
\1f
File: tar.info, Node: failing commands, Prev: extracting untrusted archives, Up: extract
tar: jazz: Not found in archive
This is because these files were not originally _in_ the parent
-directory `..', where the archive is located; they were in the
-`practice' directory, and their file names reflect this:
+directory '..', where the archive is located; they were in the
+'practice' directory, and their file names reflect this:
$ tar -tvf music.tar
practice/blues
order to extract the files from the archive.
If you have forgotten the correct names of the files in the archive,
-use `tar --list --verbose' to list them correctly.
+use 'tar --list --verbose' to list them correctly.
+
+ To extract the member named 'practice/folk', you must specify
+
+ $ tar --extract --file=music.tar practice/folk
+
+Notice also, that as explained above, the 'practice' directory will be
+created, if it didn't already exist. There are options that allow you
+to strip away a certain number of leading directory components (*note
+transform::). For example,
+
+ $ tar --extract --file=music.tar --strip-components=1 folk
+
+will extract the file 'folk' into the current working directory.
\1f
File: tar.info, Node: going further, Prev: extract, Up: Tutorial
\1f
File: tar.info, Node: tar invocation, Next: operations, Prev: Tutorial, Up: Top
-3 Invoking GNU `tar'
+3 Invoking GNU 'tar'
********************
-This chapter is about how one invokes the GNU `tar' command, from the
+This chapter is about how one invokes the GNU 'tar' command, from the
command synopsis (*note Synopsis::). There are numerous options, and
many styles for writing them. One mandatory option specifies the
-operation `tar' should perform (*note Operation Summary::), other
+operation 'tar' should perform (*note Operation Summary::), other
options are meant to detail how this operation should be performed
(*note Option Summary::). Non-option arguments are not always
interpreted the same way, depending on what the operation is.
You will find in this chapter everything about option styles and
rules for writing them (*note Styles::). On the other hand, operations
-and options are fully described elsewhere, in other chapters. Here,
-you will find only synthetic descriptions for operations and options,
-together with pointers to other parts of the `tar' manual.
+and options are fully described elsewhere, in other chapters. Here, you
+will find only synthetic descriptions for operations and options,
+together with pointers to other parts of the 'tar' manual.
Some options are so special they are fully described right in this
chapter. They have the effect of inhibiting the normal operation of
-`tar' or else, they globally alter the amount of feedback the user
-receives about what is going on. These are the `--help' and
-`--version' (*note help::), `--verbose' (*note verbose::) and
-`--interactive' options (*note interactive::).
+'tar' or else, they globally alter the amount of feedback the user
+receives about what is going on. These are the '--help' and '--version'
+(*note help::), '--verbose' (*note verbose::) and '--interactive'
+options (*note interactive::).
* Menu:
* Synopsis::
* using tar options::
* Styles::
-* All Options:: All `tar' Options.
+* All Options:: All 'tar' Options.
* help:: Where to Get Help.
* defaults:: What are the Default Values.
-* verbose:: Checking `tar' progress.
+* verbose:: Checking 'tar' progress.
* checkpoints:: Checkpoints.
* warnings:: Controlling Warning Messages.
* interactive:: Asking for Confirmation During Operations.
\1f
File: tar.info, Node: Synopsis, Next: using tar options, Up: tar invocation
-3.1 General Synopsis of `tar'
+3.1 General Synopsis of 'tar'
=============================
-The GNU `tar' program is invoked as either one of:
+The GNU 'tar' program is invoked as either one of:
tar OPTION... [NAME]...
tar LETTER... [ARGUMENT]... [OPTION]... [NAME]...
The second form is for when old options are being used.
- You can use `tar' to store files in an archive, to extract them from
+ You can use 'tar' to store files in an archive, to extract them from
an archive, and to do other types of archive manipulation. The primary
-argument to `tar', which is called the "operation", specifies which
-action to take. The other arguments to `tar' are either "options",
-which change the way `tar' performs an operation, or file names or
-archive members, which specify the files or members `tar' is to act on.
+argument to 'tar', which is called the "operation", specifies which
+action to take. The other arguments to 'tar' are either "options",
+which change the way 'tar' performs an operation, or file names or
+archive members, which specify the files or members 'tar' is to act on.
You can actually type in arguments in any order, even if in this
manual the options always precede the other arguments, to make examples
easier to understand. Further, the option stating the main operation
-mode (the `tar' main command) is usually given first.
+mode (the 'tar' main command) is usually given first.
Each NAME in the synopsis above is interpreted as an archive member
-name when the main command is one of `--compare' (`--diff', `-d'),
-`--delete', `--extract' (`--get', `-x'), `--list' (`-t') or `--update'
-(`-u'). When naming archive members, you must give the exact name of
-the member in the archive, as it is printed by `--list'. For
-`--append' (`-r') and `--create' (`-c'), these NAME arguments specify
-the names of either files or directory hierarchies to place in the
-archive. These files or hierarchies should already exist in the file
-system, prior to the execution of the `tar' command.
-
- `tar' interprets relative file names as being relative to the
-working directory. `tar' will make all file names relative (by
-removing leading slashes when archiving or restoring files), unless you
-specify otherwise (using the `--absolute-names' option). *Note
-absolute::, for more information about `--absolute-names'.
+name when the main command is one of '--compare' ('--diff', '-d'),
+'--delete', '--extract' ('--get', '-x'), '--list' ('-t') or '--update'
+('-u'). When naming archive members, you must give the exact name of
+the member in the archive, as it is printed by '--list'. For '--append'
+('-r') and '--create' ('-c'), these NAME arguments specify the names of
+either files or directory hierarchies to place in the archive. These
+files or hierarchies should already exist in the file system, prior to
+the execution of the 'tar' command.
+
+ 'tar' interprets relative file names as being relative to the working
+directory. 'tar' will make all file names relative (by removing leading
+slashes when archiving or restoring files), unless you specify otherwise
+(using the '--absolute-names' option). *Note absolute::, for more
+information about '--absolute-names'.
If you give the name of a directory as either a file name or a member
-name, then `tar' acts recursively on all the files and directories
-beneath that directory. For example, the name `/' identifies all the
-files in the file system to `tar'.
+name, then 'tar' acts recursively on all the files and directories
+beneath that directory. For example, the name '/' identifies all the
+files in the file system to 'tar'.
The distinction between file names and archive member names is
-especially important when shell globbing is used, and sometimes a
-source of confusion for newcomers. *Note wildcards::, for more
-information about globbing. The problem is that shells may only glob
-using existing files in the file system. Only `tar' itself may glob on
-archive members, so when needed, you must ensure that wildcard
-characters reach `tar' without being interpreted by the shell first.
-Using a backslash before `*' or `?', or putting the whole argument
-between quotes, is usually sufficient for this.
+especially important when shell globbing is used, and sometimes a source
+of confusion for newcomers. *Note wildcards::, for more information
+about globbing. The problem is that shells may only glob using existing
+files in the file system. Only 'tar' itself may glob on archive
+members, so when needed, you must ensure that wildcard characters reach
+'tar' without being interpreted by the shell first. Using a backslash
+before '*' or '?', or putting the whole argument between quotes, is
+usually sufficient for this.
Even if NAMEs are often specified on the command line, they can also
be read from a text file in the file system, using the
-`--files-from=FILE-OF-NAMES' (`-T FILE-OF-NAMES') option.
+'--files-from=FILE-OF-NAMES' ('-T FILE-OF-NAMES') option.
- If you don't use any file name arguments, `--append' (`-r'),
-`--delete' and `--concatenate' (`--catenate', `-A') will do nothing,
-while `--create' (`-c') will usually yield a diagnostic and inhibit
-`tar' execution. The other operations of `tar' (`--list', `--extract',
-`--compare', and `--update') will act on the entire contents of the
+ If you don't use any file name arguments, '--append' ('-r'),
+'--delete' and '--concatenate' ('--catenate', '-A') will do nothing,
+while '--create' ('-c') will usually yield a diagnostic and inhibit
+'tar' execution. The other operations of 'tar' ('--list', '--extract',
+'--compare', and '--update') will act on the entire contents of the
archive.
- Besides successful exits, GNU `tar' may fail for many reasons. Some
-reasons correspond to bad usage, that is, when the `tar' command line
-is improperly written. Errors may be encountered later, while
-processing the archive or the files. Some errors are recoverable, in
-which case the failure is delayed until `tar' has completed all its
-work. Some errors are such that it would be not meaningful, or at
-least risky, to continue processing: `tar' then aborts processing
-immediately. All abnormal exits, whether immediate or delayed, should
-always be clearly diagnosed on `stderr', after a line stating the
-nature of the error.
-
- Possible exit codes of GNU `tar' are summarized in the following
+ Besides successful exits, GNU 'tar' may fail for many reasons. Some
+reasons correspond to bad usage, that is, when the 'tar' command line is
+improperly written. Errors may be encountered later, while processing
+the archive or the files. Some errors are recoverable, in which case
+the failure is delayed until 'tar' has completed all its work. Some
+errors are such that it would be not meaningful, or at least risky, to
+continue processing: 'tar' then aborts processing immediately. All
+abnormal exits, whether immediate or delayed, should always be clearly
+diagnosed on 'stderr', after a line stating the nature of the error.
+
+ Possible exit codes of GNU 'tar' are summarized in the following
table:
0
- `Successful termination'.
+ 'Successful termination'.
1
- `Some files differ'. If tar was invoked with `--compare'
- (`--diff', `-d') command line option, this means that some files
- in the archive differ from their disk counterparts (*note
- compare::). If tar was given `--create', `--append' or `--update'
- option, this exit code means that some files were changed while
- being archived and so the resulting archive does not contain the
- exact copy of the file set.
+ 'Some files differ'. If tar was invoked with '--compare'
+ ('--diff', '-d') command line option, this means that some files in
+ the archive differ from their disk counterparts (*note compare::).
+ If tar was given '--create', '--append' or '--update' option, this
+ exit code means that some files were changed while being archived
+ and so the resulting archive does not contain the exact copy of the
+ file set.
2
- `Fatal error'. This means that some fatal, unrecoverable error
+ 'Fatal error'. This means that some fatal, unrecoverable error
occurred.
- If `tar' has invoked a subprocess and that subprocess exited with a
-nonzero exit code, `tar' exits with that code as well. This can
-happen, for example, if `tar' was given some compression option (*note
-gzip::) and the external compressor program failed. Another example is
-`rmt' failure during backup to the remote device (*note Remote Tape
-Server::).
+ If 'tar' has invoked a subprocess and that subprocess exited with a
+nonzero exit code, 'tar' exits with that code as well. This can happen,
+for example, if 'tar' was given some compression option (*note gzip::)
+and the external compressor program failed. Another example is 'rmt'
+failure during backup to the remote device (*note Remote Tape Server::).
\1f
File: tar.info, Node: using tar options, Next: Styles, Prev: Synopsis, Up: tar invocation
-3.2 Using `tar' Options
+3.2 Using 'tar' Options
=======================
-GNU `tar' has a total of eight operating modes which allow you to
+GNU 'tar' has a total of eight operating modes which allow you to
perform a variety of tasks. You are required to choose one operating
-mode each time you employ the `tar' program by specifying one, and only
-one operation as an argument to the `tar' command (the corresponding
+mode each time you employ the 'tar' program by specifying one, and only
+one operation as an argument to the 'tar' command (the corresponding
options may be found at *note frequent operations:: and *note
Operations::). Depending on circumstances, you may also wish to
customize how the chosen operating mode behaves. For example, you may
-wish to change the way the output looks, or the format of the files
-that you wish to archive may require you to do something special in
-order to make the archive look right.
+wish to change the way the output looks, or the format of the files that
+you wish to archive may require you to do something special in order to
+make the archive look right.
- You can customize and control `tar''s performance by running `tar'
-with one or more options (such as `--verbose' (`-v'), which we used in
+ You can customize and control 'tar''s performance by running 'tar'
+with one or more options (such as '--verbose' ('-v'), which we used in
the tutorial). As we said in the tutorial, "options" are arguments to
-`tar' which are (as their name suggests) optional. Depending on the
-operating mode, you may specify one or more options. Different options
+'tar' which are (as their name suggests) optional. Depending on the
+operating mode, you may specify one or more options. Different options
will have different effects, but in general they all change details of
the operation, such as archive format, archive name, or level of user
interaction. Some options make sense with all operating modes, while
-others are meaningful only with particular modes. You will likely use
+others are meaningful only with particular modes. You will likely use
some options frequently, while you will only use others infrequently, or
not at all. (A full list of options is available in *note All
Options::.)
- The `TAR_OPTIONS' environment variable specifies default options to
+ The 'TAR_OPTIONS' environment variable specifies default options to
be placed in front of any explicit options. For example, if
-`TAR_OPTIONS' is `-v --unlink-first', `tar' behaves as if the two
-options `-v' and `--unlink-first' had been specified before any
-explicit options. Option specifications are separated by whitespace.
-A backslash escapes the next character, so it can be used to specify an
+'TAR_OPTIONS' is '-v --unlink-first', 'tar' behaves as if the two
+options '-v' and '--unlink-first' had been specified before any explicit
+options. Option specifications are separated by whitespace. A
+backslash escapes the next character, so it can be used to specify an
option containing whitespace or a backslash.
- Note that `tar' options are case sensitive. For example, the
-options `-T' and `-t' are different; the first requires an argument for
-stating the name of a file providing a list of NAMEs, while the second
-does not require an argument and is another way to write `--list'
-(`-t').
+ Note that 'tar' options are case sensitive. For example, the options
+'-T' and '-t' are different; the first requires an argument for stating
+the name of a file providing a list of NAMEs, while the second does not
+require an argument and is another way to write '--list' ('-t').
- In addition to the eight operations, there are many options to
-`tar', and three different styles for writing both: long (mnemonic)
-form, short form, and old style. These styles are discussed below.
-Both the options and the operations can be written in any of these three
-styles.
+ In addition to the eight operations, there are many options to 'tar',
+and three different styles for writing both: long (mnemonic) form, short
+form, and old style. These styles are discussed below. Both the
+options and the operations can be written in any of these three styles.
\1f
File: tar.info, Node: Styles, Next: All Options, Prev: using tar options, Up: tar invocation
===========================
There are three styles for writing operations and options to the command
-line invoking `tar'. The different styles were developed at different
-times during the history of `tar'. These styles will be presented
+line invoking 'tar'. The different styles were developed at different
+times during the history of 'tar'. These styles will be presented
below, from the most recent to the oldest.
Some options must take an argument(1). Where you _place_ the
will detail specific information relevant to each option style in the
sections on the different option styles, below. The differences are
subtle, yet can often be very important; incorrect option placement can
-cause you to overwrite a number of important files. We urge you to
-note these differences, and only use the option style(s) which makes
-the most sense to you until you feel comfortable with the others.
+cause you to overwrite a number of important files. We urge you to note
+these differences, and only use the option style(s) which makes the most
+sense to you until you feel comfortable with the others.
Some options _may_ take an argument. Such options may have at most
long and short forms, they do not have old style equivalent. The rules
---------- Footnotes ----------
- (1) For example, `--file' (`-f') takes the name of an archive file
-as an argument. If you do not supply an archive file name, `tar' will
-use a default, but this can be confusing; thus, we recommend that you
-always supply a specific archive file name.
+ (1) For example, '--file' ('-f') takes the name of an archive file as
+an argument. If you do not supply an archive file name, 'tar' will use
+a default, but this can be confusing; thus, we recommend that you always
+supply a specific archive file name.
\1f
File: tar.info, Node: Long Options, Next: Short Options, Up: Styles
-----------------------
Each option has at least one "long" (or "mnemonic") name starting with
-two dashes in a row, e.g., `--list'. The long names are more clear than
+two dashes in a row, e.g., '--list'. The long names are more clear than
their corresponding short or old names. It sometimes happens that a
single long option has many different names which are synonymous, such
-as `--compare' and `--diff'. In addition, long option names can be
-given unique abbreviations. For example, `--cre' can be used in place
-of `--create' because there is no other long option which begins with
-`cre'. (One way to find this out is by trying it and seeing what
+as '--compare' and '--diff'. In addition, long option names can be
+given unique abbreviations. For example, '--cre' can be used in place
+of '--create' because there is no other long option which begins with
+'cre'. (One way to find this out is by trying it and seeing what
happens; if a particular abbreviation could represent more than one
-option, `tar' will tell you that that abbreviation is ambiguous and
+option, 'tar' will tell you that that abbreviation is ambiguous and
you'll know that that abbreviation won't work. You may also choose to
-run `tar --help' to see a list of options. Be aware that if you run
-`tar' with a unique abbreviation for the long name of an option you
-didn't want to use, you are stuck; `tar' will perform the command as
+run 'tar --help' to see a list of options. Be aware that if you run
+'tar' with a unique abbreviation for the long name of an option you
+didn't want to use, you are stuck; 'tar' will perform the command as
ordered.)
Long options are meant to be obvious and easy to remember, and their
$ tar --create --verbose --blocking-factor=20 --file=/dev/rmt0
gives a fairly good set of hints about what the command does, even for
-those not fully acquainted with `tar'.
+those not fully acquainted with 'tar'.
- Long options which require arguments take those arguments
-immediately following the option name. There are two ways of
-specifying a mandatory argument. It can be separated from the option
-name either by an equal sign, or by any amount of white space
-characters. For example, the `--file' option (which tells the name of
-the `tar' archive) is given a file such as `archive.tar' as argument by
-using any of the following notations: `--file=archive.tar' or `--file
-archive.tar'.
+ Long options which require arguments take those arguments immediately
+following the option name. There are two ways of specifying a mandatory
+argument. It can be separated from the option name either by an equal
+sign, or by any amount of white space characters. For example, the
+'--file' option (which tells the name of the 'tar' archive) is given a
+file such as 'archive.tar' as argument by using any of the following
+notations: '--file=archive.tar' or '--file archive.tar'.
In contrast, optional arguments must always be introduced using an
-equal sign. For example, the `--backup' option takes an optional
+equal sign. For example, the '--backup' option takes an optional
argument specifying backup type. It must be used as
-`--backup=BACKUP-TYPE'.
+'--backup=BACKUP-TYPE'.
\1f
File: tar.info, Node: Short Options, Next: Old Options, Prev: Long Options, Up: Styles
------------------------
Most options also have a "short option" name. Short options start with
-a single dash, and are followed by a single character, e.g., `-t'
-(which is equivalent to `--list'). The forms are absolutely identical
-in function; they are interchangeable.
+a single dash, and are followed by a single character, e.g., '-t' (which
+is equivalent to '--list'). The forms are absolutely identical in
+function; they are interchangeable.
The short option names are faster to type than long option names.
immediately following the option, usually separated by white space. It
is also possible to stick the argument right after the short option
name, using no intervening space. For example, you might write
-`-f archive.tar' or `-farchive.tar' instead of using
-`--file=archive.tar'. Both `--file=ARCHIVE-NAME' and `-f ARCHIVE-NAME'
+'-f archive.tar' or '-farchive.tar' instead of using
+'--file=archive.tar'. Both '--file=ARCHIVE-NAME' and '-f ARCHIVE-NAME'
denote the option which indicates a specific archive, here named
-`archive.tar'.
+'archive.tar'.
Short options which take optional arguments take their arguments
immediately following the option letter, _without any intervening white
space characters_.
Short options' letters may be clumped together, but you are not
-required to do this (as compared to old options; see below). When
-short options are clumped as a set, use one (single) dash for them all,
-e.g., ``tar' -cvf'. Only the last option in such a set is allowed to
-have an argument(1).
+required to do this (as compared to old options; see below). When short
+options are clumped as a set, use one (single) dash for them all, e.g.,
+''tar' -cvf'. Only the last option in such a set is allowed to have an
+argument(1).
When the options are separated, the argument for each option which
requires an argument directly follows that option, as is usual for Unix
---------- Footnotes ----------
(1) Clustering many options, the last of which has an argument, is a
-rather opaque way to write options. Some wonder if GNU `getopt' should
+rather opaque way to write options. Some wonder if GNU 'getopt' should
not even be made helpful enough for considering such usages as invalid.
\1f
3.3.3 Old Option Style
----------------------
-As far as we know, all `tar' programs, GNU and non-GNU, support "old
-options": that is, if the first argument does not start with `-', it is
-assumed to specify option letters. GNU `tar' supports old options not
+As far as we know, all 'tar' programs, GNU and non-GNU, support "old
+options": that is, if the first argument does not start with '-', it is
+assumed to specify option letters. GNU 'tar' supports old options not
only for historical reasons, but also because many people are used to
them. If the first argument does not start with a dash, you are
announcing the old option style instead of the short option style; old
options are decoded differently.
Like short options, old options are single letters. However, old
-options must be written together as a single clumped set, without
-spaces separating them or dashes preceding them. This set of letters
-must be the first to appear on the command line, after the `tar'
-program name and some white space; old options cannot appear anywhere
-else. The letter of an old option is exactly the same letter as the
-corresponding short option. For example, the old option `t' is the
-same as the short option `-t', and consequently, the same as the long
-option `--list'. So for example, the command `tar cv' specifies the
-option `-v' in addition to the operation `-c'.
+options must be written together as a single clumped set, without spaces
+separating them or dashes preceding them. This set of letters must be
+the first to appear on the command line, after the 'tar' program name
+and some white space; old options cannot appear anywhere else. The
+letter of an old option is exactly the same letter as the corresponding
+short option. For example, the old option 't' is the same as the short
+option '-t', and consequently, the same as the long option '--list'. So
+for example, the command 'tar cv' specifies the option '-v' in addition
+to the operation '-c'.
When options that need arguments are given together with the command,
all the associated arguments follow, in the same order as the options.
$ tar cvbf 20 /dev/rmt0
-Here, `20' is the argument of `-b' and `/dev/rmt0' is the argument of
-`-f'.
+Here, '20' is the argument of '-b' and '/dev/rmt0' is the argument of
+'-f'.
The old style syntax can make it difficult to match option letters
with their corresponding arguments, and is often confusing. In the
-command `tar cvbf 20 /dev/rmt0', for example, `20' is the argument for
-`-b', `/dev/rmt0' is the argument for `-f', and `-v' does not have a
+command 'tar cvbf 20 /dev/rmt0', for example, '20' is the argument for
+'-b', '/dev/rmt0' is the argument for '-f', and '-v' does not have a
corresponding argument. Even using short options like in
-`tar -c -v -b 20 -f /dev/rmt0' is clearer, putting all arguments next
-to the option they pertain to.
+'tar -c -v -b 20 -f /dev/rmt0' is clearer, putting all arguments next to
+the option they pertain to.
If you want to reorder the letters in the old option argument, be
sure to reorder any corresponding argument appropriately.
- This old way of writing `tar' options can surprise even experienced
+ This old way of writing 'tar' options can surprise even experienced
users. For example, the two commands:
tar cfz archive.tar.gz file
tar -cfz archive.tar.gz file
-are quite different. The first example uses `archive.tar.gz' as the
-value for option `f' and recognizes the option `z'. The second
-example, however, uses `z' as the value for option `f' -- probably not
-what was intended.
+are quite different. The first example uses 'archive.tar.gz' as the
+value for option 'f' and recognizes the option 'z'. The second example,
+however, uses 'z' as the value for option 'f' -- probably not what was
+intended.
This second example could be corrected in many ways, among which the
following are equivalent:
3.3.4 Mixing Option Styles
--------------------------
-All three styles may be intermixed in a single `tar' command, so long
-as the rules for each style are fully respected(1). Old style options
-and either of the modern styles of options may be mixed within a single
-`tar' command. However, old style options must be introduced as the
+All three styles may be intermixed in a single 'tar' command, so long as
+the rules for each style are fully respected(1). Old style options and
+either of the modern styles of options may be mixed within a single
+'tar' command. However, old style options must be introduced as the
first arguments only, following the rule for old options (old options
-must appear directly after the `tar' command and some white space).
+must appear directly after the 'tar' command and some white space).
Modern options may be given only after all arguments to the old options
have been collected. If this rule is not respected, a modern option
might be falsely interpreted as the value of the argument to one of the
tar f archive.tar -c
tar fc archive.tar
- On the other hand, the following commands are _not_ equivalent to
-the previous set:
+ On the other hand, the following commands are _not_ equivalent to the
+previous set:
tar -f -c archive.tar
tar -fc archive.tar
These last examples mean something completely different from what the
user intended (judging based on the example in the previous set which
uses long options, whose intent is therefore very clear). The first
-four specify that the `tar' archive would be a file named `-c', `c',
-`carchive.tar' or `archive.tarc', respectively. The first two examples
+four specify that the 'tar' archive would be a file named '-c', 'c',
+'carchive.tar' or 'archive.tarc', respectively. The first two examples
also specify a single non-option, NAME argument having the value
-`archive.tar'. The last example contains only old style option letters
-(repeating option `c' twice), not all of which are meaningful (eg., `.',
-`h', or `i'), with no argument value.
+'archive.tar'. The last example contains only old style option letters
+(repeating option 'c' twice), not all of which are meaningful (eg., '.',
+'h', or 'i'), with no argument value.
---------- Footnotes ----------
- (1) Before GNU `tar' version 1.11.6, a bug prevented intermixing old
+ (1) Before GNU 'tar' version 1.11.6, a bug prevented intermixing old
style options with long options in some cases.
\1f
File: tar.info, Node: All Options, Next: help, Prev: Styles, Up: tar invocation
-3.4 All `tar' Options
+3.4 All 'tar' Options
=====================
-The coming manual sections contain an alphabetical listing of all `tar'
+The coming manual sections contain an alphabetical listing of all 'tar'
operations and options, with brief descriptions and cross-references to
-more in-depth explanations in the body of the manual. They also
-contain an alphabetically arranged table of the short option forms with
-their corresponding long option. You can use this table as a reference
-for deciphering `tar' commands in scripts.
+more in-depth explanations in the body of the manual. They also contain
+an alphabetically arranged table of the short option forms with their
+corresponding long option. You can use this table as a reference for
+deciphering 'tar' commands in scripts.
* Menu:
* Operation Summary::
* Option Summary::
* Short Option Summary::
+* Position-Sensitive Options::
\1f
File: tar.info, Node: Operation Summary, Next: Option Summary, Up: All Options
3.4.1 Operations
----------------
-`--append'
-`-r'
+'--append'
+'-r'
+
Appends files to the end of the archive. *Note append::.
-`--catenate'
-`-A'
- Same as `--concatenate'. *Note concatenate::.
+'--catenate'
+'-A'
+
+ Same as '--concatenate'. *Note concatenate::.
+
+'--compare'
+'-d'
-`--compare'
-`-d'
Compares archive members with their counterparts in the file
system, and reports differences in file size, mode, owner,
modification date and contents. *Note compare::.
-`--concatenate'
-`-A'
- Appends other `tar' archives to the end of the archive. *Note
+'--concatenate'
+'-A'
+
+ Appends other 'tar' archives to the end of the archive. *Note
concatenate::.
-`--create'
-`-c'
- Creates a new `tar' archive. *Note create::.
+'--create'
+'-c'
+
+ Creates a new 'tar' archive. *Note create::.
+
+'--delete'
-`--delete'
Deletes members from the archive. Don't try this on an archive on
a tape! *Note delete::.
-`--diff'
-`-d'
- Same `--compare'. *Note compare::.
+'--diff'
+'-d'
+
+ Same '--compare'. *Note compare::.
+
+'--extract'
+'-x'
-`--extract'
-`-x'
Extracts members from the archive into the file system. *Note
extract::.
-`--get'
-`-x'
- Same as `--extract'. *Note extract::.
+'--get'
+'-x'
+
+ Same as '--extract'. *Note extract::.
+
+'--list'
+'-t'
-`--list'
-`-t'
Lists the members in an archive. *Note list::.
-`--update'
-`-u'
+'--update'
+'-u'
+
Adds files to the end of the archive, but only if they are newer
than their counterparts already in the archive, or if they do not
- already exist in the archive. *Note update::.
-
+ already exist in the archive. *Note update::.
\1f
File: tar.info, Node: Option Summary, Next: Short Option Summary, Prev: Operation Summary, Up: All Options
-3.4.2 `tar' Options
+3.4.2 'tar' Options
-------------------
-`--absolute-names'
-`-P'
- Normally when creating an archive, `tar' strips an initial `/'
- from member names, and when extracting from an archive `tar'
- treats names specially if they have initial `/' or internal `..'.
- This option disables that behavior. *Note absolute::.
+'--absolute-names'
+'-P'
+
+ Normally when creating an archive, 'tar' strips an initial '/' from
+ member names, and when extracting from an archive 'tar' treats
+ names specially if they have initial '/' or internal '..'. This
+ option disables that behavior. *Note absolute::.
+
+'--acls'
+ Enable POSIX ACLs support. *Note acls: Extended File Attributes.
+
+'--after-date'
-`--after-date'
- (See `--newer', *note after::)
+ (See '--newer', *note after::)
-`--anchored'
+'--anchored'
A pattern must match an initial subsequence of the name's
components. *Note controlling pattern-matching::.
-`--atime-preserve'
-`--atime-preserve=replace'
-`--atime-preserve=system'
+'--atime-preserve'
+'--atime-preserve=replace'
+'--atime-preserve=system'
+
Attempt to preserve the access time of files when reading them.
This option currently is effective only on files that you own,
unless you have superuser privileges.
- `--atime-preserve=replace' remembers the access time of a file
+ '--atime-preserve=replace' remembers the access time of a file
before reading it, and then restores the access time afterwards.
This may cause problems if other programs are reading the file at
the same time, as the times of their accesses will be lost. On
- most platforms restoring the access time also requires `tar' to
+ most platforms restoring the access time also requires 'tar' to
restore the data modification time too, so this option may also
cause problems if other programs are writing the file at the same
- time (`tar' attempts to detect this situation, but cannot do so
+ time ('tar' attempts to detect this situation, but cannot do so
reliably due to race conditions). Worse, on most platforms
restoring the access time also updates the status change time,
which means that this option is incompatible with incremental
backups.
- `--atime-preserve=system' avoids changing time stamps on files,
+ '--atime-preserve=system' avoids changing time stamps on files,
without interfering with time stamp updates caused by other
- programs, so it works better with incremental backups. However,
- it requires a special `O_NOATIME' option from the underlying
- operating and file system implementation, and it also requires
- that searching directories does not update their access times. As
- of this writing (November 2005) this works only with Linux, and
- only with Linux kernels 2.6.8 and later. Worse, there is
- currently no reliable way to know whether this feature actually
- works. Sometimes `tar' knows that it does not work, and if you use
- `--atime-preserve=system' then `tar' complains and exits right
- away. But other times `tar' might think that the option works
- when it actually does not.
-
- Currently `--atime-preserve' with no operand defaults to
- `--atime-preserve=replace', but this may change in the future as
- support for `--atime-preserve=system' improves.
+ programs, so it works better with incremental backups. However, it
+ requires a special 'O_NOATIME' option from the underlying operating
+ and file system implementation, and it also requires that searching
+ directories does not update their access times. As of this writing
+ (November 2005) this works only with Linux, and only with Linux
+ kernels 2.6.8 and later. Worse, there is currently no reliable way
+ to know whether this feature actually works. Sometimes 'tar' knows
+ that it does not work, and if you use '--atime-preserve=system'
+ then 'tar' complains and exits right away. But other times 'tar'
+ might think that the option works when it actually does not.
+
+ Currently '--atime-preserve' with no operand defaults to
+ '--atime-preserve=replace', but this may change in the future as
+ support for '--atime-preserve=system' improves.
If your operating or file system does not support
- `--atime-preserve=system', you might be able to preserve access
- times reliably by using the `mount' command. For example, you can
+ '--atime-preserve=system', you might be able to preserve access
+ times reliably by using the 'mount' command. For example, you can
mount the file system read-only, or access the file system via a
- read-only loopback mount, or use the `noatime' mount option
+ read-only loopback mount, or use the 'noatime' mount option
available on some systems. However, mounting typically requires
superuser privileges and can be a pain to manage.
-`--auto-compress'
-`-a'
- During a `--create' operation, enables automatic compressed format
- recognition based on the archive suffix. The effect of this
- option is cancelled by `--no-auto-compress'. *Note gzip::.
+'--auto-compress'
+'-a'
+
+ During a '--create' operation, enables automatic compressed format
+ recognition based on the archive suffix. The effect of this option
+ is cancelled by '--no-auto-compress'. *Note gzip::.
-`--backup=BACKUP-TYPE'
- Rather than deleting files from the file system, `tar' will back
+'--backup=BACKUP-TYPE'
+
+ Rather than deleting files from the file system, 'tar' will back
them up using simple or numbered backups, depending upon
BACKUP-TYPE. *Note backup::.
-`--block-number'
-`-R'
- With this option present, `tar' prints error messages for read
+'--block-number'
+'-R'
+
+ With this option present, 'tar' prints error messages for read
errors with the block number in the archive file. *Note
block-number::.
-`--blocking-factor=BLOCKING'
-`-b BLOCKING'
- Sets the blocking factor `tar' uses to BLOCKING x 512 bytes per
+'--blocking-factor=BLOCKING'
+'-b BLOCKING'
+
+ Sets the blocking factor 'tar' uses to BLOCKING x 512 bytes per
record. *Note Blocking Factor::.
-`--bzip2'
-`-j'
- This option tells `tar' to read or write archives through `bzip2'.
+'--bzip2'
+'-j'
+
+ This option tells 'tar' to read or write archives through 'bzip2'.
*Note gzip::.
-`--check-device'
+'--check-device'
Check device numbers when creating a list of modified files for
incremental archiving. This is the default. *Note device
numbers::, for a detailed description.
-`--checkpoint[=NUMBER]'
- This option directs `tar' to print periodic checkpoint messages as
+'--checkpoint[=NUMBER]'
+
+ This option directs 'tar' to print periodic checkpoint messages as
it reads through the archive. It is intended for when you want a
- visual indication that `tar' is still running, but don't want to
- see `--verbose' output. You can also instruct `tar' to execute a
- list of actions on each checkpoint, see `--checkpoint-action'
+ visual indication that 'tar' is still running, but don't want to
+ see '--verbose' output. You can also instruct 'tar' to execute a
+ list of actions on each checkpoint, see '--checkpoint-action'
below. For a detailed description, see *note checkpoints::.
-`--checkpoint-action=ACTION'
- Instruct `tar' to execute an action upon hitting a breakpoint.
+'--checkpoint-action=ACTION'
+ Instruct 'tar' to execute an action upon hitting a breakpoint.
Here we give only a brief outline. *Note checkpoints::, for a
complete description.
The ACTION argument can be one of the following:
- bell
+ bell
Produce an audible bell on the console.
- dot
- .
+ dot
+ .
Print a single dot on the standard listing stream.
- echo
+ echo
Display a textual message on the standard error, with the
status and number of the checkpoint. This is the default.
- echo=STRING
+ echo=STRING
Display STRING on the standard error. Before output, the
string is subject to meta-character expansion.
- exec=COMMAND
+ exec=COMMAND
Execute the given COMMAND.
- sleep=TIME
+ sleep=TIME
Wait for TIME seconds.
- ttyout=STRING
- Output STRING on the current console (`/dev/tty').
+ ttyout=STRING
+ Output STRING on the current console ('/dev/tty').
- Several `--checkpoint-action' options can be specified. The
+ Several '--checkpoint-action' options can be specified. The
supplied actions will be executed in order of their appearance in
the command line.
- Using `--checkpoint-action' without `--checkpoint' assumes default
+ Using '--checkpoint-action' without '--checkpoint' assumes default
checkpoint frequency of one checkpoint per 10 records.
-`--check-links'
-`-l'
- If this option was given, `tar' will check the number of links
+'--check-links'
+'-l'
+ If this option was given, 'tar' will check the number of links
dumped for each processed file. If this number does not match the
total number of hard links for the file, a warning message will be
output (1).
*Note hard links::.
-`--compress'
-`--uncompress'
-`-Z'
- `tar' will use the `compress' program when reading or writing the
+'--compress'
+'--uncompress'
+'-Z'
+
+ 'tar' will use the 'compress' program when reading or writing the
archive. This allows you to directly act on archives while saving
space. *Note gzip::.
-`--confirmation'
- (See `--interactive'.) *Note interactive::.
+'--clamp-mtime'
+
+ (See '--mtime'.)
+
+'--confirmation'
+
+ (See '--interactive'.) *Note interactive::.
+
+'--delay-directory-restore'
-`--delay-directory-restore'
Delay setting modification times and permissions of extracted
- directories until the end of extraction. *Note Directory
+ directories until the end of extraction. *Note Directory
Modification Times and Permissions::.
-`--dereference'
-`-h'
- When reading or writing a file to be archived, `tar' accesses the
+'--dereference'
+'-h'
+
+ When reading or writing a file to be archived, 'tar' accesses the
file that a symbolic link points to, rather than the symlink
itself. *Note dereference::.
-`--directory=DIR'
-`-C DIR'
- When this option is specified, `tar' will change its current
+'--directory=DIR'
+'-C DIR'
+
+ When this option is specified, 'tar' will change its current
directory to DIR before performing any operations. When this
option is used during archive creation, it is order sensitive.
*Note directory::.
-`--exclude=PATTERN'
- When performing operations, `tar' will skip files that match
+'--exclude=PATTERN'
+
+ When performing operations, 'tar' will skip files that match
PATTERN. *Note exclude::.
-`--exclude-backups'
+'--exclude-backups'
Exclude backup and lock files. *Note exclude-backups: exclude.
-`--exclude-from=FILE'
-`-X FILE'
- Similar to `--exclude', except `tar' will use the list of patterns
+'--exclude-from=FILE'
+'-X FILE'
+
+ Similar to '--exclude', except 'tar' will use the list of patterns
in the file FILE. *Note exclude::.
-`--exclude-caches'
+'--exclude-caches'
+
Exclude from dump any directory containing a valid cache directory
tag file, but still dump the directory node and the tag file
itself.
*Note exclude-caches: exclude.
-`--exclude-caches-under'
+'--exclude-caches-under'
+
Exclude from dump any directory containing a valid cache directory
tag file, but still dump the directory node itself.
*Note exclude::.
-`--exclude-caches-all'
+'--exclude-caches-all'
+
Exclude from dump any directory containing a valid cache directory
tag file. *Note exclude::.
-`--exclude-ignore=FILE'
- Before dumping a directory, `tar' checks if it contains FILE. If
+'--exclude-ignore=FILE'
+ Before dumping a directory, 'tar' checks if it contains FILE. If
so, exclusion patterns are read from this file. The patterns
affect only the directory itself. *Note exclude::.
-`--exclude-ignore-recursive=FILE'
- Before dumping a directory, `tar' checks if it contains FILE. If
+'--exclude-ignore-recursive=FILE'
+ Before dumping a directory, 'tar' checks if it contains FILE. If
so, exclusion patterns are read from this file. The patterns
affect the directory and all itssubdirectories. *Note exclude::.
-`--exclude-tag=FILE'
+'--exclude-tag=FILE'
+
Exclude from dump any directory containing file named FILE, but
dump the directory node and FILE itself. *Note exclude-tag:
exclude.
-`--exclude-tag-under=FILE'
+'--exclude-tag-under=FILE'
+
Exclude from dump the contents of any directory containing file
named FILE, but dump the directory node itself. *Note
exclude-tag-under: exclude.
-`--exclude-tag-all=FILE'
+'--exclude-tag-all=FILE'
+
Exclude from dump any directory containing file named FILE. *Note
exclude-tag-all: exclude.
-`--exclude-vcs'
+'--exclude-vcs'
+
Exclude from dump directories and files, that are internal for some
widely used version control systems.
*Note exclude-vcs::.
-`--exclude-vcs-ignores'
+'--exclude-vcs-ignores'
Exclude files that match patterns read from VCS-specific ignore
- files. Supported files are: `.cvsignore', `.gitignore',
- `.bzrignore', and `.hgignore'. The semantics of each file is the
- same as for the corresponding VCS, e.g. patterns read from
- `.gitignore' affect the directory and all its subdirectories.
+ files. Supported files are: '.cvsignore', '.gitignore',
+ '.bzrignore', and '.hgignore'. The semantics of each file is the
+ same as for the corresponding VCS, e.g. patterns read from
+ '.gitignore' affect the directory and all its subdirectories.
*Note exclude-vcs-ignores::.
-`--file=ARCHIVE'
-`-f ARCHIVE'
- `tar' will use the file ARCHIVE as the `tar' archive it performs
- operations on, rather than `tar''s compilation dependent default.
+'--file=ARCHIVE'
+'-f ARCHIVE'
+
+ 'tar' will use the file ARCHIVE as the 'tar' archive it performs
+ operations on, rather than 'tar''s compilation dependent default.
*Note file tutorial::.
-`--files-from=FILE'
-`-T FILE'
- `tar' will use the contents of FILE as a list of archive members
- or files to operate on, in addition to those specified on the
+'--files-from=FILE'
+'-T FILE'
+
+ 'tar' will use the contents of FILE as a list of archive members or
+ files to operate on, in addition to those specified on the
command-line. *Note files::.
-`--force-local'
- Forces `tar' to interpret the file name given to `--file' as a
+'--force-local'
+
+ Forces 'tar' to interpret the file name given to '--file' as a
local file, even if it looks like a remote tape drive name. *Note
local and remote archives::.
-`--format=FORMAT'
-`-H FORMAT'
+'--format=FORMAT'
+'-H FORMAT'
+
Selects output archive format. FORMAT may be one of the following:
- `v7'
- Creates an archive that is compatible with Unix V7 `tar'.
+ 'v7'
+ Creates an archive that is compatible with Unix V7 'tar'.
- `oldgnu'
- Creates an archive that is compatible with GNU `tar' version
+ 'oldgnu'
+ Creates an archive that is compatible with GNU 'tar' version
1.12 or earlier.
- `gnu'
+ 'gnu'
Creates archive in GNU tar 1.13 format. Basically it is the
- same as `oldgnu' with the only difference in the way it
+ same as 'oldgnu' with the only difference in the way it
handles long numeric fields.
- `ustar'
+ 'ustar'
Creates a POSIX.1-1988 compatible archive.
- `posix'
+ 'posix'
Creates a POSIX.1-2001 archive.
-
*Note Formats::, for a detailed discussion of these formats.
-`--full-time'
- This option instructs `tar' to print file times to their full
+'--full-time'
+ This option instructs 'tar' to print file times to their full
resolution. Usually this means 1-second resolution, but that
- depends on the underlying file system. The `--full-time' option
+ depends on the underlying file system. The '--full-time' option
takes effect only when detailed output (verbosity level 2 or
- higher) has been requested using the `--verbose' option, e.g.,
- when listing or extracting archives:
+ higher) has been requested using the '--verbose' option, e.g., when
+ listing or extracting archives:
$ tar -t -v --full-time -f archive.tar
$ tar -c -vv --full-time -f archive.tar .
Notice, thar when creating the archive you need to specify
- `--verbose' twice to get a detailed output (*note verbose
+ '--verbose' twice to get a detailed output (*note verbose
tutorial::).
-`--group=GROUP'
- Files added to the `tar' archive will have a group ID of GROUP,
+'--group=GROUP'
+
+ Files added to the 'tar' archive will have a group ID of GROUP,
rather than the group from the source file. GROUP can specify a
symbolic name, or a numeric ID, or both as NAME:ID. *Note
override::.
- Also see the comments for the `--owner=USER' option.
+ Also see the '--group-map' option and comments for the
+ '--owner=USER' option.
+
+'--group-map=FILE'
+
+ Read owner group translation map from FILE. This option allows to
+ translate only certain group names and/or UIDs. *Note override::,
+ for a detailed description. When used together with '--group'
+ option, the latter affects only those files whose owner group is
+ not listed in the FILE.
+
+ This option does not affect extraction from archives.
-`--gzip'
-`--gunzip'
-`--ungzip'
-`-z'
- This option tells `tar' to read or write archives through `gzip',
- allowing `tar' to directly operate on several kinds of compressed
+'--gzip'
+'--gunzip'
+'--ungzip'
+'-z'
+
+ This option tells 'tar' to read or write archives through 'gzip',
+ allowing 'tar' to directly operate on several kinds of compressed
archives transparently. *Note gzip::.
-`--hard-dereference'
+'--hard-dereference'
When creating an archive, dereference hard links and store the
files they refer to, instead of creating usual hard link members.
*Note hard links::.
-`--help'
-`-?'
- `tar' will print out a short message summarizing the operations and
- options to `tar' and exit. *Note help::.
+'--help'
+'-?'
+
+ 'tar' will print out a short message summarizing the operations and
+ options to 'tar' and exit. *Note help::.
-`--ignore-case'
+'--hole-detection=METHOD'
+ Use METHOD to detect holes in sparse files. This option implies
+ '--sparse'. Valid methods are 'seek' and 'raw'. Default is 'seek'
+ with fallback to 'raw' when not applicable. *Note sparse::.
+
+'--ignore-case'
Ignore case when matching member or file names with patterns.
*Note controlling pattern-matching::.
-`--ignore-command-error'
- Ignore exit codes of subprocesses. *Note Writing to an External
+'--ignore-command-error'
+ Ignore exit codes of subprocesses. *Note Writing to an External
Program::.
-`--ignore-failed-read'
+'--ignore-failed-read'
+
Do not exit unsuccessfully merely because an unreadable file was
encountered. *Note Ignore Failed Read::.
-`--ignore-zeros'
-`-i'
- With this option, `tar' will ignore zeroed blocks in the archive,
- which normally signals EOF. *Note Reading::.
+'--ignore-zeros'
+'-i'
-`--incremental'
-`-G'
- Informs `tar' that it is working with an old GNU-format
- incremental backup archive. It is intended primarily for
- backwards compatibility only. *Note Incremental Dumps::, for a
- detailed discussion of incremental archives.
+ With this option, 'tar' will ignore zeroed blocks in the archive,
+ which normally signals EOF. *Note Reading::.
+
+'--incremental'
+'-G'
+
+ Informs 'tar' that it is working with an old GNU-format incremental
+ backup archive. It is intended primarily for backwards
+ compatibility only. *Note Incremental Dumps::, for a detailed
+ discussion of incremental archives.
+
+'--index-file=FILE'
-`--index-file=FILE'
Send verbose output to FILE instead of to standard output.
-`--info-script=COMMAND'
-`--new-volume-script=COMMAND'
-`-F COMMAND'
- When `tar' is performing multi-tape backups, COMMAND is run at the
- end of each tape. If it exits with nonzero status, `tar' fails
+'--info-script=COMMAND'
+'--new-volume-script=COMMAND'
+'-F COMMAND'
+
+ When 'tar' is performing multi-tape backups, COMMAND is run at the
+ end of each tape. If it exits with nonzero status, 'tar' fails
immediately. *Note info-script::, for a detailed discussion of
this feature.
-`--interactive'
-`--confirmation'
-`-w'
- Specifies that `tar' should ask the user for confirmation before
+'--interactive'
+'--confirmation'
+'-w'
+
+ Specifies that 'tar' should ask the user for confirmation before
performing potentially destructive options, such as overwriting
files. *Note interactive::.
-`--keep-directory-symlink'
+'--keep-directory-symlink'
+
This option changes the behavior of tar when it encounters a
symlink with the same name as the directory that it is about to
extract. By default, in this case tar would first remove the
symlink and then proceed extracting the directory.
- The `--keep-directory-symlink' option disables this behavior and
+ The '--keep-directory-symlink' option disables this behavior and
instructs tar to follow symlinks to directories when extracting
from the archive.
It is mainly intended to provide compatibility with the Slackware
installation scripts.
-`--keep-newer-files'
+'--keep-newer-files'
+
Do not replace existing files that are newer than their archive
copies when extracting files from an archive.
-`--keep-old-files'
-`-k'
+'--keep-old-files'
+'-k'
+
Do not overwrite existing files when extracting files from an
archive. Return error if such files exist. See also *note
--skip-old-files::.
*Note Keep Old Files::.
-`--label=NAME'
-`-V NAME'
- When creating an archive, instructs `tar' to write NAME as a name
- record in the archive. When extracting or listing archives, `tar'
+'--label=NAME'
+'-V NAME'
+
+ When creating an archive, instructs 'tar' to write NAME as a name
+ record in the archive. When extracting or listing archives, 'tar'
will only operate on archives that have a label matching the
pattern specified in NAME. *Note Tape Files::.
-`--level=N'
- Force incremental backup of level N. As of GNU `tar' version
- 1.28, the option `--level=0' truncates the snapshot file, thereby
- forcing the level 0 dump. Other values of N are effectively
- ignored. *Note --level=0::, for details and examples.
+'--level=N'
+ Force incremental backup of level N. As of GNU 'tar' version 1.29,
+ the option '--level=0' truncates the snapshot file, thereby forcing
+ the level 0 dump. Other values of N are effectively ignored.
+ *Note --level=0::, for details and examples.
The use of this option is valid only in conjunction with the
- `--listed-incremental' option. *Note Incremental Dumps::, for a
+ '--listed-incremental' option. *Note Incremental Dumps::, for a
detailed description.
-`--listed-incremental=SNAPSHOT-FILE'
-`-g SNAPSHOT-FILE'
- During a `--create' operation, specifies that the archive that
- `tar' creates is a new GNU-format incremental backup, using
+'--listed-incremental=SNAPSHOT-FILE'
+'-g SNAPSHOT-FILE'
+
+ During a '--create' operation, specifies that the archive that
+ 'tar' creates is a new GNU-format incremental backup, using
SNAPSHOT-FILE to determine which files to backup. With other
- operations, informs `tar' that the archive is in incremental
+ operations, informs 'tar' that the archive is in incremental
format. *Note Incremental Dumps::.
-`--lzip'
- This option tells `tar' to read or write archives through `lzip'.
+'--lzip'
+
+ This option tells 'tar' to read or write archives through 'lzip'.
*Note gzip::.
-`--lzma'
- This option tells `tar' to read or write archives through `lzma'.
+'--lzma'
+
+ This option tells 'tar' to read or write archives through 'lzma'.
*Note gzip::.
-`--lzop'
- This option tells `tar' to read or write archives through `lzop'.
+'--lzop'
+
+ This option tells 'tar' to read or write archives through 'lzop'.
*Note gzip::.
-`--mode=PERMISSIONS'
- When adding files to an archive, `tar' will use PERMISSIONS for
- the archive members, rather than the permissions from the files.
+'--mode=PERMISSIONS'
+
+ When adding files to an archive, 'tar' will use PERMISSIONS for the
+ archive members, rather than the permissions from the files.
PERMISSIONS can be specified either as an octal number or as
- symbolic permissions, like with `chmod'. *Note override::.
+ symbolic permissions, like with 'chmod'. *Note override::.
+
+'--mtime=DATE'
-`--mtime=DATE'
- When adding files to an archive, `tar' will use DATE as the
+ When adding files to an archive, 'tar' will use DATE as the
modification time of members when creating archives, instead of
- their actual modification times. The value of DATE can be either
- a textual date representation (*note Date input formats::) or a
- name of the existing file, starting with `/' or `.'. In the
- latter case, the modification time of that file is used. *Note
+ their actual modification times. The value of DATE can be either a
+ textual date representation (*note Date input formats::) or a name
+ of the existing file, starting with '/' or '.'. In the latter
+ case, the modification time of that file is used. *Note
override::.
-`--multi-volume'
-`-M'
- Informs `tar' that it should create or otherwise operate on a
- multi-volume `tar' archive. *Note Using Multiple Tapes::.
-
-`--new-volume-script'
- (see `--info-script')
-
-`--newer=DATE'
-`--after-date=DATE'
-`-N'
- When creating an archive, `tar' will only add files that have
- changed since DATE. If DATE begins with `/' or `.', it is taken
- to be the name of a file whose data modification time specifies
- the date. *Note after::.
-
-`--newer-mtime=DATE'
- Like `--newer', but add only files whose contents have changed (as
- opposed to just `--newer', which will also back up files for which
+ When '--clamp-mtime' is also specified, files with modification
+ times earlier than DATE will retain their actual modification
+ times, and DATE will only be used for files whose modification
+ times are later than DATE.
+
+'--multi-volume'
+'-M'
+
+ Informs 'tar' that it should create or otherwise operate on a
+ multi-volume 'tar' archive. *Note Using Multiple Tapes::.
+
+'--new-volume-script'
+
+ (see '--info-script')
+
+'--newer=DATE'
+'--after-date=DATE'
+'-N'
+
+ When creating an archive, 'tar' will only add files that have
+ changed since DATE. If DATE begins with '/' or '.', it is taken to
+ be the name of a file whose data modification time specifies the
+ date. *Note after::.
+
+'--newer-mtime=DATE'
+
+ Like '--newer', but add only files whose contents have changed (as
+ opposed to just '--newer', which will also back up files for which
any status information has changed). *Note after::.
-`--no-anchored'
+'--no-acls'
+ Disable the POSIX ACLs support. *Note acls: Extended File
+ Attributes.
+
+'--no-anchored'
An exclude pattern can match any subsequence of the name's
components. *Note controlling pattern-matching::.
-`--no-auto-compress'
+'--no-auto-compress'
+
Disables automatic compressed format recognition based on the
archive suffix. *Note --auto-compress::. *Note gzip::.
-`--no-check-device'
+'--no-check-device'
Do not check device numbers when creating a list of modified files
for incremental archiving. *Note device numbers::, for a detailed
description.
-`--no-delay-directory-restore'
- Modification times and permissions of extracted directories are
- set when all files from this directory have been extracted. This
- is the default. *Note Directory Modification Times and
- Permissions::.
+'--no-delay-directory-restore'
+
+ Modification times and permissions of extracted directories are set
+ when all files from this directory have been extracted. This is
+ the default. *Note Directory Modification Times and Permissions::.
-`--no-ignore-case'
+'--no-ignore-case'
Use case-sensitive matching. *Note controlling pattern-matching::.
-`--no-ignore-command-error'
+'--no-ignore-command-error'
Print warnings about subprocesses that terminated with a nonzero
- exit code. *Note Writing to an External Program::.
+ exit code. *Note Writing to an External Program::.
-`--no-null'
- If the `--null' option was given previously, this option cancels
- its effect, so that any following `--files-from' options will
+'--no-null'
+
+ If the '--null' option was given previously, this option cancels
+ its effect, so that any following '--files-from' options will
expect their file lists to be newline-terminated.
-`--no-overwrite-dir'
+'--no-overwrite-dir'
+
Preserve metadata of existing directories when extracting files
from an archive. *Note Overwrite Old Files::.
-`--no-quote-chars=STRING'
+'--no-quote-chars=STRING'
Remove characters listed in STRING from the list of quoted
- characters set by the previous `--quote-chars' option (*note
+ characters set by the previous '--quote-chars' option (*note
quoting styles::).
-`--no-recursion'
- With this option, `tar' will not recurse into directories. *Note
+'--no-recursion'
+
+ With this option, 'tar' will not recurse into directories. *Note
recurse::.
-`--no-same-owner'
-`-o'
+'--no-same-owner'
+'-o'
+
When extracting an archive, do not attempt to preserve the owner
- specified in the `tar' archive. This the default behavior for
+ specified in the 'tar' archive. This the default behavior for
ordinary users.
-`--no-same-permissions'
+'--no-same-permissions'
+
When extracting an archive, subtract the user's umask from files
- from the permissions specified in the archive. This is the
- default behavior for ordinary users.
+ from the permissions specified in the archive. This is the default
+ behavior for ordinary users.
+
+'--no-seek'
-`--no-seek'
The archive media does not support seeks to arbitrary locations.
- Usually `tar' determines automatically whether the archive can be
+ Usually 'tar' determines automatically whether the archive can be
seeked or not. Use this option to disable this mechanism.
-`--no-unquote'
+'--no-selinux'
+ Disable SELinux context support. *Note SELinux: Extended File
+ Attributes.
+
+'--no-unquote'
Treat all input file or member names literally, do not interpret
escape sequences. *Note input name quoting::.
-`--no-wildcards'
+'--no-verbatim-files-from'
+
+ Instructs GNU 'tar' to treat each line read from a file list as if
+ it were supplied in the command line. I.e., leading and trailing
+ whitespace is removed and, if the result begins with a dash, it is
+ treated as a GNU 'tar' command line option.
+
+ This is default behavior. This option is provided as a way to
+ restore it after '--verbatim-files-from' option.
+
+ It is implied by the '--no-null' option.
+
+ *Note no-verbatim-files-from::.
+
+'--no-wildcards'
Do not use wildcards. *Note controlling pattern-matching::.
-`--no-wildcards-match-slash'
- Wildcards do not match `/'. *Note controlling pattern-matching::.
+'--no-wildcards-match-slash'
+ Wildcards do not match '/'. *Note controlling pattern-matching::.
+
+'--no-xattrs'
+ Disable extended attributes support. *Note xattrs: Extended File
+ Attributes.
+
+'--null'
+
+ When 'tar' is using the '--files-from' option, this option
+ instructs 'tar' to expect file names terminated with NUL, and to
+ process file names verbatim.
+
+ This means that 'tar' correctly works with file names that contain
+ newlines or begin with a dash.
+
+ *Note nul::.
+
+ See also *note verbatim-files-from::.
-`--null'
- When `tar' is using the `--files-from' option, this option
- instructs `tar' to expect file names terminated with NUL, so `tar'
- can correctly work with file names that contain newlines. *Note
- nul::.
+'--numeric-owner'
-`--numeric-owner'
- This option will notify `tar' that it should use numeric user and
- group IDs when creating a `tar' file, rather than names. *Note
+ This option will notify 'tar' that it should use numeric user and
+ group IDs when creating a 'tar' file, rather than names. *Note
Attributes::.
-`-o'
- The function of this option depends on the action `tar' is
- performing. When extracting files, `-o' is a synonym for
- `--no-same-owner', i.e., it prevents `tar' from restoring
- ownership of files being extracted.
+'-o'
+ The function of this option depends on the action 'tar' is
+ performing. When extracting files, '-o' is a synonym for
+ '--no-same-owner', i.e., it prevents 'tar' from restoring ownership
+ of files being extracted.
- When creating an archive, it is a synonym for `--old-archive'.
+ When creating an archive, it is a synonym for '--old-archive'.
This behavior is for compatibility with previous versions of GNU
- `tar', and will be removed in future releases.
+ 'tar', and will be removed in future releases.
*Note Changes::, for more information.
-`--occurrence[=NUMBER]'
+'--occurrence[=NUMBER]'
+
This option can be used in conjunction with one of the subcommands
- `--delete', `--diff', `--extract' or `--list' when a list of files
- is given either on the command line or via `-T' option.
+ '--delete', '--diff', '--extract' or '--list' when a list of files
+ is given either on the command line or via '-T' option.
- This option instructs `tar' to process only the NUMBERth
- occurrence of each named file. NUMBER defaults to 1, so
+ This option instructs 'tar' to process only the NUMBERth occurrence
+ of each named file. NUMBER defaults to 1, so
tar -x -f archive.tar --occurrence filename
- will extract the first occurrence of the member `filename' from
- `archive.tar' and will terminate without scanning to the end of
- the archive.
+ will extract the first occurrence of the member 'filename' from
+ 'archive.tar' and will terminate without scanning to the end of the
+ archive.
-`--old-archive'
- Synonym for `--format=v7'.
+'--old-archive'
+ Synonym for '--format=v7'.
-`--one-file-system'
- Used when creating an archive. Prevents `tar' from recursing into
+'--one-file-system'
+ Used when creating an archive. Prevents 'tar' from recursing into
directories that are on different file systems from the current
directory.
-`--one-top-level[=DIR]'
- Tells `tar' to create a new directory beneath the extraction
- directory (or the one passed to `-C') and use it to guard against
+'--one-top-level[=DIR]'
+ Tells 'tar' to create a new directory beneath the extraction
+ directory (or the one passed to '-C') and use it to guard against
tarbombs. In the absence of DIR argument, the name of the new
directory will be equal to the base name of the archive (file name
- minus the archive suffix, if recognized). Any member names that
- do not begin with that directory name (after transformations from
- `--transform' and `--strip-components') will be prefixed with it.
- Recognized file name suffixes are `.tar', and any compression
+ minus the archive suffix, if recognized). Any member names that do
+ not begin with that directory name (after transformations from
+ '--transform' and '--strip-components') will be prefixed with it.
+ Recognized file name suffixes are '.tar', and any compression
suffixes recognizable by *Note --auto-compress::.
-`--overwrite'
+'--overwrite'
+
Overwrite existing files and directory metadata when extracting
files from an archive. *Note Overwrite Old Files::.
-`--overwrite-dir'
+'--overwrite-dir'
+
Overwrite the metadata of existing directories when extracting
files from an archive. *Note Overwrite Old Files::.
-`--owner=USER'
- Specifies that `tar' should use USER as the owner of members when
+'--owner=USER'
+
+ Specifies that 'tar' should use USER as the owner of members when
creating archives, instead of the user associated with the source
file. USER can specify a symbolic name, or a numeric ID, or both
as NAME:ID. *Note override::.
+ This option does not affect extraction from archives. See also
+ '--owner-map', below.
+
+'--owner-map=FILE'
+
+ Read owner translation map from FILE. This option allows to
+ translate only certain owner names or UIDs. *Note override::, for
+ a detailed description. When used together with '--owner' option,
+ the latter affects only those files whose owner is not listed in
+ the FILE.
+
This option does not affect extraction from archives.
-`--pax-option=KEYWORD-LIST'
+'--pax-option=KEYWORD-LIST'
This option enables creation of the archive in POSIX.1-2001 format
- (*note posix::) and modifies the way `tar' handles the extended
- header keywords. KEYWORD-LIST is a comma-separated list of
- keyword options. *Note PAX keywords::, for a detailed discussion.
+ (*note posix::) and modifies the way 'tar' handles the extended
+ header keywords. KEYWORD-LIST is a comma-separated list of keyword
+ options. *Note PAX keywords::, for a detailed discussion.
+
+'--portability'
+'--old-archive'
+ Synonym for '--format=v7'.
-`--portability'
-`--old-archive'
- Synonym for `--format=v7'.
+'--posix'
+ Same as '--format=posix'.
-`--posix'
- Same as `--format=posix'.
+'--preserve-order'
-`--preserve'
- Synonymous with specifying both `--preserve-permissions' and
- `--same-order'. *Note Setting Access Permissions::.
+ (See '--same-order'; *note Reading::.)
-`--preserve-order'
- (See `--same-order'; *note Reading::.)
+'--preserve-permissions'
+'--same-permissions'
+'-p'
-`--preserve-permissions'
-`--same-permissions'
-`-p'
- When `tar' is extracting an archive, it normally subtracts the
+ When 'tar' is extracting an archive, it normally subtracts the
users' umask from the permissions specified in the archive and uses
that number as the permissions to create the destination file.
- Specifying this option instructs `tar' that it should use the
+ Specifying this option instructs 'tar' that it should use the
permissions directly from the archive. *Note Setting Access
Permissions::.
-`--quote-chars=STRING'
+'--quote-chars=STRING'
Always quote characters from STRING, even if the selected quoting
style would not quote them (*note quoting styles::).
-`--quoting-style=STYLE'
- Set quoting style to use when printing member and file names
- (*note quoting styles::). Valid STYLE values are: `literal',
- `shell', `shell-always', `c', `escape', `locale', and `clocale'.
- Default quoting style is `escape', unless overridden while
- configuring the package.
+'--quoting-style=STYLE'
+ Set quoting style to use when printing member and file names (*note
+ quoting styles::). Valid STYLE values are: 'literal', 'shell',
+ 'shell-always', 'c', 'escape', 'locale', and 'clocale'. Default
+ quoting style is 'escape', unless overridden while configuring the
+ package.
-`--read-full-records'
-`-B'
- Specifies that `tar' should reblock its input, for reading from
+'--read-full-records'
+'-B'
+
+ Specifies that 'tar' should reblock its input, for reading from
pipes on systems with buggy implementations. *Note Reading::.
-`--record-size=SIZE[SUF]'
- Instructs `tar' to use SIZE bytes per record when accessing the
+'--record-size=SIZE[SUF]'
+
+ Instructs 'tar' to use SIZE bytes per record when accessing the
archive. The argument can be suffixed with a "size suffix", e.g.
- `--record-size=10K' for 10 Kilobytes. *Note size-suffixes::, for
- a list of valid suffixes. *Note Blocking Factor::, for a detailed
- description of this option.
+ '--record-size=10K' for 10 Kilobytes. *Note Table 9.1:
+ size-suffixes, for a list of valid suffixes. *Note Blocking
+ Factor::, for a detailed description of this option.
-`--recursion'
- With this option, `tar' recurses into directories (default).
- *Note recurse::.
+'--recursion'
+
+ With this option, 'tar' recurses into directories (default). *Note
+ recurse::.
+
+'--recursive-unlink'
-`--recursive-unlink'
- Remove existing directory hierarchies before extracting
- directories of the same name from the archive. *Note Recursive
- Unlink::.
+ Remove existing directory hierarchies before extracting directories
+ of the same name from the archive. *Note Recursive Unlink::.
-`--remove-files'
- Directs `tar' to remove the source file from the file system after
+'--remove-files'
+
+ Directs 'tar' to remove the source file from the file system after
appending it to an archive. *Note remove files::.
-`--restrict'
- Disable use of some potentially harmful `tar' options. Currently
- this option disables shell invocation from multi-volume menu
- (*note Using Multiple Tapes::).
+'--restrict'
+
+ Disable use of some potentially harmful 'tar' options. Currently
+ this option disables shell invocation from multi-volume menu (*note
+ Using Multiple Tapes::).
-`--rmt-command=CMD'
- Notifies `tar' that it should use CMD instead of the default
- `/usr/libexec/rmt' (*note Remote Tape Server::).
+'--rmt-command=CMD'
-`--rsh-command=CMD'
- Notifies `tar' that is should use CMD to communicate with remote
+ Notifies 'tar' that it should use CMD instead of the default
+ '/usr/libexec/rmt' (*note Remote Tape Server::).
+
+'--rsh-command=CMD'
+
+ Notifies 'tar' that is should use CMD to communicate with remote
devices. *Note Device::.
-`--same-order'
-`--preserve-order'
-`-s'
- This option is an optimization for `tar' when running on machines
- with small amounts of memory. It informs `tar' that the list of
+'--same-order'
+'--preserve-order'
+'-s'
+
+ This option is an optimization for 'tar' when running on machines
+ with small amounts of memory. It informs 'tar' that the list of
file arguments has already been sorted to match the order of files
in the archive. *Note Reading::.
-`--same-owner'
- When extracting an archive, `tar' will attempt to preserve the
- owner specified in the `tar' archive with this option present.
+'--same-owner'
+
+ When extracting an archive, 'tar' will attempt to preserve the
+ owner specified in the 'tar' archive with this option present.
This is the default behavior for the superuser; this option has an
effect only for ordinary users. *Note Attributes::.
-`--same-permissions'
- (See `--preserve-permissions'; *note Setting Access Permissions::.)
+'--same-permissions'
+
+ (See '--preserve-permissions'; *note Setting Access Permissions::.)
+
+'--seek'
+'-n'
-`--seek'
-`-n'
Assume that the archive media supports seeks to arbitrary
- locations. Usually `tar' determines automatically whether the
+ locations. Usually 'tar' determines automatically whether the
archive can be seeked or not. This option is intended for use in
cases when such recognition fails. It takes effect only if the
- archive is open for reading (e.g. with `--list' or `--extract'
+ archive is open for reading (e.g. with '--list' or '--extract'
options).
-`--show-defaults'
- Displays the default options used by `tar' and exits successfully.
+'--selinux'
+ Enable the SELinux context support. *Note selinux: Extended File
+ Attributes.
+
+'--show-defaults'
+
+ Displays the default options used by 'tar' and exits successfully.
This option is intended for use in shell scripts. Here is an
example of what you can see using this option:
--rmt-command=/usr/libexec/rmt --rsh-command=/usr/bin/rsh
Notice, that this option outputs only one line. The example output
- above has been split to fit page boundaries. *Note defaults::.
+ above has been split to fit page boundaries. *Note defaults::.
-`--show-omitted-dirs'
- Instructs `tar' to mention the directories it is skipping when
- operating on a `tar' archive. *Note show-omitted-dirs::.
+'--show-omitted-dirs'
-`--show-snapshot-field-ranges'
- Displays the range of values allowed by this version of `tar' for
+ Instructs 'tar' to mention the directories it is skipping when
+ operating on a 'tar' archive. *Note show-omitted-dirs::.
+
+'--show-snapshot-field-ranges'
+
+ Displays the range of values allowed by this version of 'tar' for
each field in the snapshot file, then exits successfully. *Note
Snapshot Files::.
-`--show-transformed-names'
-`--show-stored-names'
+'--show-transformed-names'
+'--show-stored-names'
+
Display file or member names after applying any transformations
(*note transform::). In particular, when used in conjunction with
- one of the archive creation operations it instructs `tar' to list
+ one of the archive creation operations it instructs 'tar' to list
the member names stored in the archive, as opposed to the actual
file names. *Note listing member and file names::.
-`--skip-old-files'
+'--skip-old-files'
+
Do not overwrite existing files when extracting files from an
archive. *Note Keep Old Files::.
- This option differs from `--keep-old-files' in that it does not
+ This option differs from '--keep-old-files' in that it does not
treat such files as an error, instead it just silently avoids
overwriting them.
- The `--warning=existing-file' option can be used together with
- this option to produce warning messages about existing old files
- (*note warnings::).
+ The '--warning=existing-file' option can be used together with this
+ option to produce warning messages about existing old files (*note
+ warnings::).
-`--sort=ORDER'
+'--sort=ORDER'
Specify the directory sorting order when reading directories.
ORDER may be one of the following:
- `none'
- No directory sorting is performed. This is the default.
+ 'none'
+ No directory sorting is performed. This is the default.
- `name'
- Sort the directory entries on name. The operating system may
+ 'name'
+ Sort the directory entries on name. The operating system may
deliver directory entries in a more or less random order, and
sorting them makes archive creation reproducible.
- `inode'
- Sort the directory entries on inode number. Sorting
- directories on inode number may reduce the amount of disk
- seek operations when creating an archive for some file
- systems.
+ 'inode'
+ Sort the directory entries on inode number. Sorting
+ directories on inode number may reduce the amount of disk seek
+ operations when creating an archive for some file systems.
+'--sparse'
+'-S'
-`--sparse'
-`-S'
Invokes a GNU extension when adding files to an archive that
handles sparse files efficiently. *Note sparse::.
-`--sparse-version=VERSION'
+'--sparse-version=VERSION'
+
Specifies the "format version" to use when archiving sparse files.
- Implies `--sparse'. *Note sparse::. For the description of the
+ Implies '--sparse'. *Note sparse::. For the description of the
supported sparse formats, *Note Sparse Formats::.
-`--starting-file=NAME'
-`-K NAME'
- This option affects extraction only; `tar' will skip extracting
+'--starting-file=NAME'
+'-K NAME'
+
+ This option affects extraction only; 'tar' will skip extracting
files in the archive until it finds one that matches NAME. *Note
Scarce::.
-`--strip-components=NUMBER'
+'--strip-components=NUMBER'
Strip given NUMBER of leading components from file names before
- extraction. For example, if archive `archive.tar' contained
- `/some/file/name', then running
+ extraction. For example, if archive 'archive.tar' contained
+ '/some/file/name', then running
tar --extract --file archive.tar --strip-components=2
- would extract this file to file `name'.
+ would extract this file to file 'name'.
+
+ *Note transform::.
-`--suffix=SUFFIX'
- Alters the suffix `tar' uses when backing up files from the default
- `~'. *Note backup::.
+'--suffix=SUFFIX'
-`--tape-length=NUM[SUF]'
-`-L NUM[SUF]'
- Specifies the length of tapes that `tar' is writing as being
+ Alters the suffix 'tar' uses when backing up files from the default
+ '~'. *Note backup::.
+
+'--tape-length=NUM[SUF]'
+'-L NUM[SUF]'
+
+ Specifies the length of tapes that 'tar' is writing as being
NUM x 1024 bytes long. If optional SUF is given, it specifies a
multiplicative factor to be used instead of 1024. For example,
- `-L2M' means 2 megabytes. *Note size-suffixes::, for a list of
- allowed suffixes. *Note Using Multiple Tapes::, for a detailed
- discussion of this option.
+ '-L2M' means 2 megabytes. *Note Table 9.1: size-suffixes, for a
+ list of allowed suffixes. *Note Using Multiple Tapes::, for a
+ detailed discussion of this option.
+
+'--test-label'
-`--test-label'
Reads the volume label. If an argument is specified, test whether
it matches the volume label. *Note --test-label option::.
-`--to-command=COMMAND'
- During extraction `tar' will pipe extracted files to the standard
+'--to-command=COMMAND'
+
+ During extraction 'tar' will pipe extracted files to the standard
input of COMMAND. *Note Writing to an External Program::.
-`--to-stdout'
-`-O'
- During extraction, `tar' will extract files to stdout rather than
+'--to-stdout'
+'-O'
+
+ During extraction, 'tar' will extract files to stdout rather than
to the file system. *Note Writing to Standard Output::.
-`--totals[=SIGNO]'
+'--totals[=SIGNO]'
+
Displays the total number of bytes transferred when processing an
archive. If an argument is given, these data are displayed on
- request, when signal SIGNO is delivered to `tar'. *Note totals::.
+ request, when signal SIGNO is delivered to 'tar'. *Note totals::.
+
+'--touch'
+'-m'
-`--touch'
-`-m'
Sets the data modification time of extracted files to the
extraction time, rather than the data modification time stored in
the archive. *Note Data Modification Times::.
-`--transform=SED-EXPR'
-`--xform=SED-EXPR'
- Transform file or member names using `sed' replacement expression
+'--transform=SED-EXPR'
+'--xform=SED-EXPR'
+ Transform file or member names using 'sed' replacement expression
SED-EXPR. For example,
$ tar cf archive.tar --transform 's,^\./,usr/,' .
- will add to `archive' files from the current working directory,
- replacing initial `./' prefix with `usr/'. For the detailed
+ will add to 'archive' files from the current working directory,
+ replacing initial './' prefix with 'usr/'. For the detailed
discussion, *Note transform::.
To see transformed member names in verbose listings, use
- `--show-transformed-names' option (*note show-transformed-names::).
+ '--show-transformed-names' option (*note show-transformed-names::).
+
+'--uncompress'
+
+ (See '--compress', *note gzip::)
-`--uncompress'
- (See `--compress', *note gzip::)
+'--ungzip'
-`--ungzip'
- (See `--gzip', *note gzip::)
+ (See '--gzip', *note gzip::)
-`--unlink-first'
-`-U'
- Directs `tar' to remove the corresponding file from the file
- system before extracting it from the archive. *Note Unlink
- First::.
+'--unlink-first'
+'-U'
-`--unquote'
- Enable unquoting input file or member names (default). *Note
- input name quoting::.
+ Directs 'tar' to remove the corresponding file from the file system
+ before extracting it from the archive. *Note Unlink First::.
-`--use-compress-program=PROG'
-`-I=PROG'
- Instructs `tar' to access the archive through PROG, which is
+'--unquote'
+ Enable unquoting input file or member names (default). *Note input
+ name quoting::.
+
+'--use-compress-program=PROG'
+'-I=PROG'
+
+ Instructs 'tar' to access the archive through PROG, which is
presumed to be a compression program of some sort. *Note gzip::.
-`--utc'
+'--utc'
+
Display file modification dates in UTC. This option implies
- `--verbose'.
+ '--verbose'.
+
+'--verbatim-files-from'
+
+ Instructs GNU 'tar' to treat each line read from a file list as a
+ file name, even if it starts with a dash.
+
+ File lists are supplied with the '--files-from' ('-T') option. By
+ default, each line read from a file list is first trimmed off the
+ leading and trailing whitespace and, if the result begins with a
+ dash, it is treated as a GNU 'tar' command line option.
+
+ Use the '--verbatim-files-from' option to disable this special
+ handling. This facilitates the use of 'tar' with file lists
+ created by 'file' command.
+
+ This option affects all '--files-from' options that occur after it
+ in the command line. Its effect is reverted by the
+ '--no-verbatim-files-from' option.
-`--verbose'
-`-v'
- Specifies that `tar' should be more verbose about the operations
- it is performing. This option can be specified multiple times for
+ This option is implied by the '--null' option.
+
+ *Note verbatim-files-from::.
+
+'--verbose'
+'-v'
+
+ Specifies that 'tar' should be more verbose about the operations it
+ is performing. This option can be specified multiple times for
some operations to increase the amount of information displayed.
*Note verbose::.
-`--verify'
-`-W'
+'--verify'
+'-W'
+
Verifies that the archive was correctly written when creating an
archive. *Note verify::.
-`--version'
+'--version'
+
Print information about the program's name, version, origin and
legal status, all on standard output, and then exit successfully.
*Note help::.
-`--volno-file=FILE'
- Used in conjunction with `--multi-volume'. `tar' will keep track
+'--volno-file=FILE'
+
+ Used in conjunction with '--multi-volume'. 'tar' will keep track
of which volume of a multi-volume archive it is working in FILE.
*Note volno-file::.
-`--warning=KEYWORD'
+'--warning=KEYWORD'
+
Enable or disable warning messages identified by KEYWORD. The
- messages are suppressed if KEYWORD is prefixed with `no-'. *Note
+ messages are suppressed if KEYWORD is prefixed with 'no-'. *Note
warnings::.
-`--wildcards'
+'--wildcards'
Use wildcards when matching member names with patterns. *Note
controlling pattern-matching::.
-`--wildcards-match-slash'
- Wildcards match `/'. *Note controlling pattern-matching::.
+'--wildcards-match-slash'
+ Wildcards match '/'. *Note controlling pattern-matching::.
-`--xz'
-`-J'
- Use `xz' for compressing or decompressing the archives. *Note
- gzip::.
+'--xattrs'
+ Enable extended attributes support. *Note xattrs: Extended File
+ Attributes.
+'--xattrs-exclude=PATTERN'
+ Specify exclude pattern for xattr keys. *Note xattrs-exclude:
+ Extended File Attributes.
+
+'--xattrs-include=PATTERN.'
+ Specify include pattern for xattr keys. PATTERN is a POSIX regular
+ expression, e.g. '--xattrs-exclude='^user\.'' to include only
+ attributes from the user namespace. *Note xattrs-include: Extended
+ File Attributes.
+
+'--xz'
+'-J'
+ Use 'xz' for compressing or decompressing the archives. *Note
+ gzip::.
---------- Footnotes ----------
- (1) Earlier versions of GNU `tar' understood `-l' as a synonym for
-`--one-file-system'. The current semantics, which complies to UNIX98,
-was introduced with version 1.15.91. *Note Changes::, for more
+ (1) Earlier versions of GNU 'tar' understood '-l' as a synonym for
+'--one-file-system'. The current semantics, which complies to UNIX98,
+was introduced with version 1.15.91. *Note Changes::, for more
information.
\1f
-File: tar.info, Node: Short Option Summary, Prev: Option Summary, Up: All Options
+File: tar.info, Node: Short Option Summary, Next: Position-Sensitive Options, Prev: Option Summary, Up: All Options
3.4.3 Short Options Cross Reference
-----------------------------------
them with the equivalent long option.
Short Option Reference
---------------------------------------------------------------------------
+
+--------------------------------------------------------------------------
-A *note --concatenate::.
+
-B *note --read-full-records::.
+
-C *note --directory::.
+
-F *note --info-script::.
+
-G *note --incremental::.
+
-J *note --xz::.
+
-K *note --starting-file::.
+
-L *note --tape-length::.
+
-M *note --multi-volume::.
+
-N *note --newer::.
+
-O *note --to-stdout::.
+
-P *note --absolute-names::.
+
-R *note --block-number::.
+
-S *note --sparse::.
+
-T *note --files-from::.
+
-U *note --unlink-first::.
+
-V *note --label::.
+
-W *note --verify::.
+
-X *note --exclude-from::.
+
-Z *note --compress::.
+
-b *note --blocking-factor::.
+
-c *note --create::.
+
-d *note --compare::.
+
-f *note --file::.
+
-g *note --listed-incremental::.
+
-h *note --dereference::.
+
-i *note --ignore-zeros::.
+
-j *note --bzip2::.
+
-k *note --keep-old-files::.
+
-l *note --check-links::.
+
-m *note --touch::.
--o When creating, *note --no-same-owner::, when extracting --
- *note --portability::.
- The latter usage is deprecated. It is retained for
- compatibility with the earlier versions of GNU `tar'. In
- future releases `-o' will be equivalent to
- `--no-same-owner' only.
+-o When creating, *note --no-same-owner::, when extracting
+ -- *note --portability::.
+
+ The latter usage is deprecated. It is retained for
+ compatibility with the earlier versions of GNU 'tar'.
+ In future releases '-o' will be equivalent to
+ '--no-same-owner' only.
+
-p *note --preserve-permissions::.
+
-r *note --append::.
+
-s *note --same-order::.
+
-t *note --list::.
+
-u *note --update::.
+
-v *note --verbose::.
+
-w *note --interactive::.
+
-x *note --extract::.
+
-z *note --gzip::.
+
+
+\1f
+File: tar.info, Node: Position-Sensitive Options, Prev: Short Option Summary, Up: All Options
+
+3.4.4 Position-Sensitive Options
+--------------------------------
+
+Some GNU 'tar' options can be used multiple times in the same invocation
+and affect all arguments that appear after them. These are options that
+control how file names are selected and what kind of pattern matching is
+used.
+
+ The most obvious example is the '-C' option. It instructs 'tar' to
+change to the directory given as its argument prior to processing the
+rest of command line (*note directory::). Thus, in the following
+command:
+
+ tar -c -f a.tar -C /etc passwd -C /var log spool
+
+the file 'passwd' will be searched in the directory '/etc', and files
+'log' and 'spool' - in '/var'.
+
+ These options can also be used in a file list supplied with the
+'--files-from' ('-T') option (*note files::). In that case they affect
+all files (patterns) appearing in that file after them and remain in
+effect for any arguments processed after that file. For example, if the
+file 'list.txt' contained:
+
+ README
+ -C src
+ main.c
+
+and 'tar' were invoked as follows:
+
+ tar -c -f a.tar -T list.txt Makefile
+
+then the file 'README' would be looked up in the current working
+directory, and files 'main.c' and 'Makefile' would be looked up in the
+directory 'src'.
+
+ Many options can be prefixed with '--no-' to cancel the effect of the
+original option.
+
+ For example, the '--recursion' option controls whether to recurse in
+the subdirectories. It's counterpart '--no-recursion' disables this.
+Consider the command below. It will store in the archive the directory
+'/usr' with all files and directories that are located in it as well as
+any files and directories in '/var', without recursing into them(1):
+
+ tar -cf a.tar --recursion /usr --no-recursion /var/*
+
+ The following table summarizes all position-sensitive options.
+
+'--directory=DIR'
+'-C DIR'
+ *Note directory::.
+
+'--null'
+'--no-null'
+ *Note nul::.
+
+'--unquote'
+'--no-unquote'
+ *Note input name quoting::.
+
+'--verbatim-files-from'
+'--no-verbatim-files-from'
+ *Note verbatim-files-from::.
+
+'--recursion'
+'--no-recursion'
+ *Note recurse::.
+
+'--anchored'
+'--no-anchored'
+ *Note anchored patterns::.
+
+'--ignore-case'
+'--no-ignore-case'
+ *Note case-insensitive matches::.
+
+'--wildcards'
+'--no-wildcards'
+ *Note controlling pattern-matching::.
+
+'--wildcards-match-slash'
+'--no-wildcards-match-slash'
+ *Note controlling pattern-matching::.
+
+'--exclude'
+ *Note exclude::.
+
+'--exclude-from'
+'-X'
+'--exclude-caches'
+'--exclude-caches-under'
+'--exclude-caches-all'
+'--exclude-tag'
+'--exclude-ignore'
+'--exclude-ignore-recursive'
+'--exclude-tag-under'
+'--exclude-tag-all'
+'--exclude-vcs'
+'--exclude-vcs-ignores'
+'--exclude-backups'
+ *Note exclude::.
+
+ ---------- Footnotes ----------
+
+ (1) The '--recursion' option is the default and is used here for
+clarity. The same example can be written as:
+
+ tar -cf a.tar /usr --no-recursion /var/*
\1f
File: tar.info, Node: help, Next: defaults, Prev: All Options, Up: tar invocation
-3.5 GNU `tar' documentation
+3.5 GNU 'tar' documentation
===========================
-Being careful, the first thing is really checking that you are using
-GNU `tar', indeed. The `--version' option causes `tar' to print
-information about its name, version, origin and legal status, all on
-standard output, and then exit successfully. For example,
-`tar --version' might print:
+Being careful, the first thing is really checking that you are using GNU
+'tar', indeed. The '--version' option causes 'tar' to print information
+about its name, version, origin and legal status, all on standard
+output, and then exit successfully. For example, 'tar --version' might
+print:
- tar (GNU tar) 1.28
- Copyright (C) 2013-2014 Free Software Foundation, Inc.
+ tar (GNU tar) 1.29
+ Copyright (C) 2013-2016 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Written by John Gilmore and Jay Fenlason.
-The first occurrence of `tar' in the result above is the program name
-in the package (for example, `rmt' is another program), while the
-second occurrence of `tar' is the name of the package itself,
-containing possibly many programs. The package is currently named
-`tar', after the name of the main program it contains(1).
+The first occurrence of 'tar' in the result above is the program name in
+the package (for example, 'rmt' is another program), while the second
+occurrence of 'tar' is the name of the package itself, containing
+possibly many programs. The package is currently named 'tar', after the
+name of the main program it contains(1).
Another thing you might want to do is checking the spelling or
-meaning of some particular `tar' option, without resorting to this
-manual, for once you have carefully read it. GNU `tar' has a short
-help feature, triggerable through the `--help' option. By using this
-option, `tar' will print a usage message listing all available options
-on standard output, then exit successfully, without doing anything else
-and ignoring all other options. Even if this is only a brief summary,
-it may be several screens long. So, if you are not using some kind of
+meaning of some particular 'tar' option, without resorting to this
+manual, for once you have carefully read it. GNU 'tar' has a short help
+feature, triggerable through the '--help' option. By using this option,
+'tar' will print a usage message listing all available options on
+standard output, then exit successfully, without doing anything else and
+ignoring all other options. Even if this is only a brief summary, it
+may be several screens long. So, if you are not using some kind of
scrollable window, you might prefer to use something like:
$ tar --help | less
-presuming, here, that you like using `less' for a pager. Other popular
-pagers are `more' and `pg'. If you know about some KEYWORD which
-interests you and do not want to read all the `--help' output, another
+presuming, here, that you like using 'less' for a pager. Other popular
+pagers are 'more' and 'pg'. If you know about some KEYWORD which
+interests you and do not want to read all the '--help' output, another
common idiom is doing:
tar --help | grep KEYWORD
-for getting only the pertinent lines. Notice, however, that some `tar'
-options have long description lines and the above command will list
-only the first of them.
+for getting only the pertinent lines. Notice, however, that some 'tar'
+options have long description lines and the above command will list only
+the first of them.
- The exact look of the option summary displayed by `tar --help' is
-configurable. *Note Configuring Help Summary::, for a detailed
+ The exact look of the option summary displayed by 'tar --help' is
+configurable. *Note Configuring Help Summary::, for a detailed
description.
- If you only wish to check the spelling of an option, running `tar
+ If you only wish to check the spelling of an option, running 'tar
--usage' may be a better choice. This will display a terse list of
-`tar' options without accompanying explanations.
+'tar' options without accompanying explanations.
The short help output is quite succinct, and you might have to get
back to the full documentation for precise points. If you are reading
-this paragraph, you already have the `tar' manual in some form. This
+this paragraph, you already have the 'tar' manual in some form. This
manual is available in a variety of forms from
-`http://www.gnu.org/software/tar/manual'. It may be printed out of the
-GNU `tar' distribution, provided you have TeX already installed
-somewhere, and a laser printer around. Just configure the
-distribution, execute the command `make dvi', then print `doc/tar.dvi'
-the usual way (contact your local guru to know how). If GNU `tar' has
-been conveniently installed at your place, this manual is also
-available in interactive, hypertextual form as an Info file. Just call
-`info tar' or, if you do not have the `info' program handy, use the
-Info reader provided within GNU Emacs, calling `tar' from the main Info
-menu.
-
- There is currently no `man' page for GNU `tar'. If you observe such
-a `man' page on the system you are running, either it does not belong
-to GNU `tar', or it has not been produced by GNU. Some package
-maintainers convert `tar --help' output to a man page, using
-`help2man'. In any case, please bear in mind that the authoritative
-source of information about GNU `tar' is this Texinfo documentation.
+<http://www.gnu.org/software/tar/manual>. It may be printed out of the
+GNU 'tar' distribution, provided you have TeX already installed
+somewhere, and a laser printer around. Just configure the distribution,
+execute the command 'make dvi', then print 'doc/tar.dvi' the usual way
+(contact your local guru to know how). If GNU 'tar' has been
+conveniently installed at your place, this manual is also available in
+interactive, hypertextual form as an Info file. Just call 'info tar'
+or, if you do not have the 'info' program handy, use the Info reader
+provided within GNU Emacs, calling 'tar' from the main Info menu.
+
+ There is currently no 'man' page for GNU 'tar'. If you observe such
+a 'man' page on the system you are running, either it does not belong to
+GNU 'tar', or it has not been produced by GNU. Some package maintainers
+convert 'tar --help' output to a man page, using 'help2man'. In any
+case, please bear in mind that the authoritative source of information
+about GNU 'tar' is this Texinfo documentation.
---------- Footnotes ----------
- (1) There are plans to merge the `cpio' and `tar' packages into a
-single one which would be called `paxutils'. So, who knows if, one of
-this days, the `--version' would not output `tar (GNU paxutils) 3.2'.
+ (1) There are plans to merge the 'cpio' and 'tar' packages into a
+single one which would be called 'paxutils'. So, who knows if, one of
+this days, the '--version' would not output 'tar (GNU paxutils) 3.2'.
\1f
File: tar.info, Node: defaults, Next: verbose, Prev: help, Up: tar invocation
-3.6 Obtaining GNU `tar' default values
+3.6 Obtaining GNU 'tar' default values
======================================
-GNU `tar' has some predefined defaults that are used when you do not
+GNU 'tar' has some predefined defaults that are used when you do not
explicitly specify another values. To obtain a list of such defaults,
-use `--show-defaults' option. This will output the values in the form
-of `tar' command line options:
+use '--show-defaults' option. This will output the values in the form
+of 'tar' command line options:
$ tar --show-defaults
--format=gnu -f- -b20 --quoting-style=escape
Notice, that this option outputs only one line. The example output
above has been split to fit page boundaries.
-The above output shows that this version of GNU `tar' defaults to using
-`gnu' archive format (*note Formats::), it uses standard output as the
-archive, if no `--file' option has been given (*note file tutorial::),
+The above output shows that this version of GNU 'tar' defaults to using
+'gnu' archive format (*note Formats::), it uses standard output as the
+archive, if no '--file' option has been given (*note file tutorial::),
the default blocking factor is 20 (*note Blocking Factor::). It also
-shows the default locations where `tar' will look for `rmt' and `rsh'
+shows the default locations where 'tar' will look for 'rmt' and 'rsh'
binaries.
\1f
File: tar.info, Node: verbose, Next: checkpoints, Prev: defaults, Up: tar invocation
-3.7 Checking `tar' progress
+3.7 Checking 'tar' progress
===========================
-Typically, `tar' performs most operations without reporting any
-information to the user except error messages. When using `tar' with
-many options, particularly ones with complicated or
-difficult-to-predict behavior, it is possible to make serious mistakes.
-`tar' provides several options that make observing `tar' easier. These
-options cause `tar' to print information as it progresses in its job,
-and you might want to use them just for being more careful about what
-is going on, or merely for entertaining yourself. If you have
-encountered a problem when operating on an archive, however, you may
-need more information than just an error message in order to solve the
-problem. The following options can be helpful diagnostic tools.
-
- Normally, the `--list' (`-t') command to list an archive prints just
-the file names (one per line) and the other commands are silent. When
-used with most operations, the `--verbose' (`-v') option causes `tar'
-to print the name of each file or archive member as it is processed.
-This and the other options which make `tar' print status information
-can be useful in monitoring `tar'.
-
- With `--create' or `--extract', `--verbose' used once just prints
-the names of the files or members as they are processed. Using it
-twice causes `tar' to print a longer listing (*Note verbose member
-listing::, for the description) for each member. Since `--list'
-already prints the names of the members, `--verbose' used once with
-`--list' causes `tar' to print an `ls -l' type listing of the files in
-the archive. The following examples both extract members with long
-list output:
+Typically, 'tar' performs most operations without reporting any
+information to the user except error messages. When using 'tar' with
+many options, particularly ones with complicated or difficult-to-predict
+behavior, it is possible to make serious mistakes. 'tar' provides
+several options that make observing 'tar' easier. These options cause
+'tar' to print information as it progresses in its job, and you might
+want to use them just for being more careful about what is going on, or
+merely for entertaining yourself. If you have encountered a problem
+when operating on an archive, however, you may need more information
+than just an error message in order to solve the problem. The following
+options can be helpful diagnostic tools.
+
+ Normally, the '--list' ('-t') command to list an archive prints just
+the file names (one per line) and the other commands are silent. When
+used with most operations, the '--verbose' ('-v') option causes 'tar' to
+print the name of each file or archive member as it is processed. This
+and the other options which make 'tar' print status information can be
+useful in monitoring 'tar'.
+
+ With '--create' or '--extract', '--verbose' used once just prints the
+names of the files or members as they are processed. Using it twice
+causes 'tar' to print a longer listing (*Note verbose member listing::,
+for the description) for each member. Since '--list' already prints the
+names of the members, '--verbose' used once with '--list' causes 'tar'
+to print an 'ls -l' type listing of the files in the archive. The
+following examples both extract members with long list output:
$ tar --extract --file=archive.tar --verbose --verbose
$ tar xvvf archive.tar
Verbose output appears on the standard output except when an archive
-is being written to the standard output, as with `tar --create --file=-
---verbose' (`tar cvf -', or even `tar cv'--if the installer let
-standard output be the default archive). In that case `tar' writes
-verbose output to the standard error stream.
+is being written to the standard output, as with 'tar --create --file=-
+--verbose' ('tar cvf -', or even 'tar cv'--if the installer let standard
+output be the default archive). In that case 'tar' writes verbose
+output to the standard error stream.
- If `--index-file=FILE' is specified, `tar' sends verbose output to
+ If '--index-file=FILE' is specified, 'tar' sends verbose output to
FILE rather than to standard output or standard error.
- The `--totals' option causes `tar' to print on the standard error
-the total amount of bytes transferred when processing an archive. When
+ The '--totals' option causes 'tar' to print on the standard error the
+total amount of bytes transferred when processing an archive. When
creating or appending to an archive, this option prints the number of
bytes written to the archive and the average speed at which they have
been written, e.g.:
$ tar -x -f archive.tar --totals
Total bytes read: 7924664320 (7.4GiB, 95MiB/s)
- Finally, when deleting from an archive, the `--totals' option
+ Finally, when deleting from an archive, the '--totals' option
displays both numbers plus number of bytes removed from the archive:
$ tar --delete -f foo.tar --totals --wildcards '*~'
Total bytes written: 3829760 (3.7MiB, 81MiB/s)
Total bytes deleted: 1474048
- You can also obtain this information on request. When `--totals' is
+ You can also obtain this information on request. When '--totals' is
used with an argument, this argument is interpreted as a symbolic name
of a signal, upon delivery of which the statistics is to be printed:
-`--totals=SIGNO'
+'--totals=SIGNO'
Print statistics upon delivery of signal SIGNO. Valid arguments
- are: `SIGHUP', `SIGQUIT', `SIGINT', `SIGUSR1' and `SIGUSR2'.
- Shortened names without `SIG' prefix are also accepted.
+ are: 'SIGHUP', 'SIGQUIT', 'SIGINT', 'SIGUSR1' and 'SIGUSR2'.
+ Shortened names without 'SIG' prefix are also accepted.
- Both forms of `--totals' option can be used simultaneously. Thus,
-`tar -x --totals --totals=USR1' instructs `tar' to extract all members
+ Both forms of '--totals' option can be used simultaneously. Thus,
+'tar -x --totals --totals=USR1' instructs 'tar' to extract all members
from its default archive and print statistics after finishing the
-extraction, as well as when receiving signal `SIGUSR1'.
+extraction, as well as when receiving signal 'SIGUSR1'.
- The `--checkpoint' option prints an occasional message as `tar'
-reads or writes the archive. It is designed for those who don't need
-the more detailed (and voluminous) output of `--block-number' (`-R'),
-but do want visual confirmation that `tar' is actually making forward
-progress. By default it prints a message each 10 records read or
-written. This can be changed by giving it a numeric argument after an
-equal sign:
+ The '--checkpoint' option prints an occasional message as 'tar' reads
+or writes the archive. It is designed for those who don't need the more
+detailed (and voluminous) output of '--block-number' ('-R'), but do want
+visual confirmation that 'tar' is actually making forward progress. By
+default it prints a message each 10 records read or written. This can
+be changed by giving it a numeric argument after an equal sign:
$ tar -c --checkpoint=1000 /var
tar: Write checkpoint 1000
tar: Write checkpoint 2000
tar: Write checkpoint 3000
- This example shows the default checkpoint message used by `tar'. If
-you place a dot immediately after the equal sign, it will print a `.'
-at each checkpoint(1). For example:
+ This example shows the default checkpoint message used by 'tar'. If
+you place a dot immediately after the equal sign, it will print a '.' at
+each checkpoint(1). For example:
$ tar -c --checkpoint=.1000 /var
...
- The `--checkpoint' option provides a flexible mechanism for
-executing arbitrary actions upon hitting checkpoints, see the next
-section (*note checkpoints::), for more information on it.
+ The '--checkpoint' option provides a flexible mechanism for executing
+arbitrary actions upon hitting checkpoints, see the next section (*note
+checkpoints::), for more information on it.
- The `--show-omitted-dirs' option, when reading an archive--with
-`--list' or `--extract', for example--causes a message to be printed
-for each directory in the archive which is skipped. This happens
-regardless of the reason for skipping: the directory might not have
-been named on the command line (implicitly or explicitly), it might be
-excluded by the use of the `--exclude=PATTERN' option, or some other
-reason.
+ The '--show-omitted-dirs' option, when reading an archive--with
+'--list' or '--extract', for example--causes a message to be printed for
+each directory in the archive which is skipped. This happens regardless
+of the reason for skipping: the directory might not have been named on
+the command line (implicitly or explicitly), it might be excluded by the
+use of the '--exclude=PATTERN' option, or some other reason.
- If `--block-number' (`-R') is used, `tar' prints, along with every
+ If '--block-number' ('-R') is used, 'tar' prints, along with every
message it would normally produce, the block number within the archive
where the message was triggered. Also, supplementary messages are
triggered when reading blocks full of NULs, or when hitting end of file
-on the archive. As of now, if the archive is properly terminated with
-a NUL block, the reading of the file may stop before end of file is
-met, so the position of end of file will not usually show when
-`--block-number' (`-R') is used. Note that GNU `tar' drains the
-archive before exiting when reading the archive from a pipe.
+on the archive. As of now, if the archive is properly terminated with a
+NUL block, the reading of the file may stop before end of file is met,
+so the position of end of file will not usually show when
+'--block-number' ('-R') is used. Note that GNU 'tar' drains the archive
+before exiting when reading the archive from a pipe.
This option is especially useful when reading damaged archives, since
it helps pinpoint the damaged sections. It can also be used with
-`--list' (`-t') when listing a file-system backup tape, allowing you to
-choose among several backup tapes when retrieving a file later, in
-favor of the tape where the file appears earliest (closest to the front
-of the tape). *Note backup::.
+'--list' ('-t') when listing a file-system backup tape, allowing you to
+choose among several backup tapes when retrieving a file later, in favor
+of the tape where the file appears earliest (closest to the front of the
+tape). *Note backup::.
---------- Footnotes ----------
- (1) This is actually a shortcut for `--checkpoint=N
+ (1) This is actually a shortcut for '--checkpoint=N
--checkpoint-action=dot'. *Note dot: checkpoints.
\1f
The checkpoint facility is enabled using the following option:
-`--checkpoint[=N]'
+'--checkpoint[=N]'
Schedule checkpoints before writing or reading each Nth record.
The default value for N is 10.
A list of arbitrary "actions" can be executed at each checkpoint.
These actions include: pausing, displaying textual messages, and
executing arbitrary external programs. Actions are defined using the
-`--checkpoint-action' option.
+'--checkpoint-action' option.
-`--checkpoint-action=ACTION'
+'--checkpoint-action=ACTION'
Execute an ACTION at each checkpoint.
- The simplest value of ACTION is `echo'. It instructs `tar' to
+ The simplest value of ACTION is 'echo'. It instructs 'tar' to
display the default message on the standard error stream upon arriving
-at each checkpoint. The default message is (in POSIX locale) `Write
-checkpoint N', for write checkpoints, and `Read checkpoint N', for read
+at each checkpoint. The default message is (in POSIX locale) 'Write
+checkpoint N', for write checkpoints, and 'Read checkpoint N', for read
checkpoints. Here, N represents ordinal number of the checkpoint.
In another locales, translated versions of this message are used.
$ tar -c --checkpoint=1000 /var
- The `echo' action also allows to supply a customized message. You
-do so by placing an equals sign and the message right after it, e.g.:
+ The 'echo' action also allows to supply a customized message. You do
+so by placing an equals sign and the message right after it, e.g.:
--checkpoint-action="echo=Hit %s checkpoint #%u"
- The `%s' and `%u' in the above example are "format specifiers". The
-`%s' specifier is replaced with the "type" of the checkpoint: `write' or
-`read' (or a corresponding translated version in locales other than
-POSIX). The `%u' specifier is replaced with the ordinal number of the
+ The '%s' and '%u' in the above example are "format specifiers". The
+'%s' specifier is replaced with the "type" of the checkpoint: 'write' or
+'read' (or a corresponding translated version in locales other than
+POSIX). The '%u' specifier is replaced with the ordinal number of the
checkpoint. Thus, the above example could produce the following output
-when used with the `--create' option:
+when used with the '--create' option:
tar: Hit write checkpoint #10
tar: Hit write checkpoint #20
supplied in curly braces between the percent sign and the specifier
letter.
-`%s'
- Print type of the checkpoint (`write' or `read').
+'%s'
+ Print type of the checkpoint ('write' or 'read').
-`%u'
+'%u'
Print number of the checkpoint.
-`%{r,w,d}T'
+'%{r,w,d}T'
Print number of bytes transferred so far and approximate transfer
speed. Optional arguments supply prefixes to be used before number
of bytes read, written and deleted, correspondingly. If absent,
- they default to `R'. `W', `D'. Any or all of them can be omitted,
- so, that e.g. `%{}T' means to print corresponding statistics
+ they default to 'R'. 'W', 'D'. Any or all of them can be omitted,
+ so, that e.g. '%{}T' means to print corresponding statistics
without any prefixes. Any surplus arguments, if present, are
silently ignored.
tar: #1: R: 0 (0B, 0B/s),W: 0 (0B, 0B/s),D: 0
tar: #2: R: 10240 (10KiB, 19MiB/s),W: 0 (0B, 0B/s),D: 10240
- See also the `totals' action, described below.
+ See also the 'totals' action, described below.
-`%{FMT}t'
- Output current local time using FMT as format for `strftime'
- (*note strftime: (strftime(3))strftime.). The `{FMT}' part is
- optional. If not present, the default format is `%c', i.e. the
- preferred date and time representation for the current locale.
+'%{FMT}t'
+ Output current local time using FMT as format for 'strftime' (*note
+ strftime: (strftime(3))strftime.). The '{FMT}' part is optional.
+ If not present, the default format is '%c', i.e. the preferred
+ date and time representation for the current locale.
-`%{N}*'
- Pad output with spaces to the Nth column. If the `{N}' part is
+'%{N}*'
+ Pad output with spaces to the Nth column. If the '{N}' part is
omitted, the current screen width is assumed.
-`%c'
- This is a shortcut for `%{%Y-%m-%d %H:%M:%S}t: %ds,
- %{read,wrote}T%*\r', intended mainly for use with `ttyout' action
+'%c'
+ This is a shortcut for '%{%Y-%m-%d %H:%M:%S}t: %ds,
+ %{read,wrote}T%*\r', intended mainly for use with 'ttyout' action
(see below).
Aside from format expansion, the message string is subject to
"unquoting", during which the backslash "escape sequences" are replaced
with their corresponding ASCII characters (*note escape sequences::).
-E.g. the following action will produce an audible bell and the message
+E.g. the following action will produce an audible bell and the message
described above at each checkpoint:
--checkpoint-action='echo=\aHit %s checkpoint #%u'
There is also a special action which produces an audible signal:
-`bell'. It is not equivalent to `echo='\a'', because `bell' sends the
-bell directly to the console (`/dev/tty'), whereas `echo='\a'' sends it
+'bell'. It is not equivalent to 'echo='\a'', because 'bell' sends the
+bell directly to the console ('/dev/tty'), whereas 'echo='\a'' sends it
to the standard error.
- The `ttyout=STRING' action outputs STRING to `/dev/tty', so it can
-be used even if the standard output is redirected elsewhere. The
-STRING is subject to the same modifications as with `echo' action. In
-contrast to the latter, `ttyout' does not prepend `tar' executable name
-to the string, nor does it output a newline after it. For example, the
+ The 'ttyout=STRING' action outputs STRING to '/dev/tty', so it can be
+used even if the standard output is redirected elsewhere. The STRING is
+subject to the same modifications as with 'echo' action. In contrast to
+the latter, 'ttyout' does not prepend 'tar' executable name to the
+string, nor does it output a newline after it. For example, the
following action will print the checkpoint message at the same screen
line, overwriting any previous message:
--checkpoint-action="ttyout=Hit %s checkpoint #%u%*\r"
-Notice the use of `%*' specifier to clear out any eventual remains of
+Notice the use of '%*' specifier to clear out any eventual remains of
the prior output line. As as more complex example, consider this:
--checkpoint-action=ttyout='%{%Y-%m-%d %H:%M:%S}t (%d sec): #%u, %T%*\r'
was started, the checkpoint ordinal number, transferred bytes and
average computed I/O speed.
- Another available checkpoint action is `dot' (or `.'). It instructs
-`tar' to print a single dot on the standard listing stream, e.g.:
+ Another available checkpoint action is 'dot' (or '.'). It instructs
+'tar' to print a single dot on the standard listing stream, e.g.:
$ tar -c --checkpoint=1000 --checkpoint-action=dot /var
...
- For compatibility with previous GNU `tar' versions, this action can
-be abbreviated by placing a dot in front of the checkpoint frequency,
-as shown in the previous section.
+ For compatibility with previous GNU 'tar' versions, this action can
+be abbreviated by placing a dot in front of the checkpoint frequency, as
+shown in the previous section.
- The `totals' action prints the total number of bytes transferred so
-far. The format of the data is the same as for the `--totals' option
-(*note totals::). See also `%T' format specifier of the `echo' or
-`ttyout' action.
+ The 'totals' action prints the total number of bytes transferred so
+far. The format of the data is the same as for the '--totals' option
+(*note totals::). See also '%T' format specifier of the 'echo' or
+'ttyout' action.
- Yet another action, `sleep', pauses `tar' for a specified amount of
+ Yet another action, 'sleep', pauses 'tar' for a specified amount of
seconds. The following example will stop for 30 seconds at each
checkpoint:
$ tar -c --checkpoint=1000 --checkpoint-action=sleep=30
- Finally, the `exec' action executes a given external command. For
+ Finally, the 'exec' action executes a given external command. For
example:
$ tar -c --checkpoint=1000 --checkpoint-action=exec=/sbin/cpoint
arguments, don't forget to quote it to prevent it from being split by
the shell. *Note Running External Commands: external, for more detail.
- The command gets a copy of `tar''s environment plus the following
+ The command gets a copy of 'tar''s environment plus the following
variables:
-`TAR_VERSION'
- GNU `tar' version number.
+'TAR_VERSION'
+ GNU 'tar' version number.
-`TAR_ARCHIVE'
- The name of the archive `tar' is processing.
+'TAR_ARCHIVE'
+ The name of the archive 'tar' is processing.
-`TAR_BLOCKING_FACTOR'
+'TAR_BLOCKING_FACTOR'
Current blocking factor (*note Blocking::).
-`TAR_CHECKPOINT'
+'TAR_CHECKPOINT'
Number of the checkpoint.
-`TAR_SUBCOMMAND'
- A short option describing the operation `tar' is executing. *Note
+'TAR_SUBCOMMAND'
+ A short option describing the operation 'tar' is executing. *Note
Operations::, for a complete list of subcommand options.
-`TAR_FORMAT'
- Format of the archive being processed. *Note Formats::, for a
+'TAR_FORMAT'
+ Format of the archive being processed. *Note Formats::, for a
complete list of archive format names.
These environment variables can also be passed as arguments to the
command, provided that they are properly escaped, for example:
tar -c -f arc.tar \
- --checkpoint-action='exec=/sbin/cpoint $TAR_FILENAME'
+ --checkpoint-action='exec=/sbin/cpoint $TAR_CHECKPOINT'
Notice single quotes to prevent variable names from being expanded by
-the shell when invoking `tar'.
+the shell when invoking 'tar'.
Any number of actions can be defined, by supplying several
-`--checkpoint-action' options in the command line. For example, the
-command below displays two messages, pauses execution for 30 seconds
-and executes the `/sbin/cpoint' script:
+'--checkpoint-action' options in the command line. For example, the
+command below displays two messages, pauses execution for 30 seconds and
+executes the '/sbin/cpoint' script:
$ tar -c -f arc.tar \
--checkpoint-action='\aecho=Hit %s checkpoint #%u' \
--checkpoint-action='sleep=30' \
--checkpoint-action='exec=/sbin/cpoint'
- This example also illustrates the fact that `--checkpoint-action'
-can be used without `--checkpoint'. In this case, the default
-checkpoint frequency (at each 10th record) is assumed.
+ This example also illustrates the fact that '--checkpoint-action' can
+be used without '--checkpoint'. In this case, the default checkpoint
+frequency (at each 10th record) is assumed.
\1f
File: tar.info, Node: warnings, Next: interactive, Prev: checkpoints, Up: tar invocation
3.9 Controlling Warning Messages
================================
-Sometimes, while performing the requested task, GNU `tar' notices some
+Sometimes, while performing the requested task, GNU 'tar' notices some
conditions that are not exactly errors, but which the user should be
-aware of. When this happens, `tar' issues a "warning message"
+aware of. When this happens, 'tar' issues a "warning message"
describing the condition. Warning messages are output to the standard
-error and they do not affect the exit code of `tar' command.
+error and they do not affect the exit code of 'tar' command.
- GNU `tar' allows the user to suppress some or all of its warning
+ GNU 'tar' allows the user to suppress some or all of its warning
messages:
-`--warning=KEYWORD'
+'--warning=KEYWORD'
Control display of the warning messages identified by KEYWORD. If
- KEYWORD starts with the prefix `no-', such messages are
- suppressed. Otherwise, they are enabled.
+ KEYWORD starts with the prefix 'no-', such messages are suppressed.
+ Otherwise, they are enabled.
- Multiple `--warning' messages accumulate.
+ Multiple '--warning' messages accumulate.
The tables below list allowed values for KEYWORD along with the
warning messages they control.
-Keywords controlling `tar' operation
+Keywords controlling 'tar' operation
------------------------------------
all
- Enable all warning messages. This is the default.
-
+ Enable all warning messages. This is the default.
none
- Disable all warning messages.
-
+ Disable all warning messages.
filename-with-nuls
- `%s: file name read contains nul character'
-
+ '%s: file name read contains nul character'
alone-zero-block
- `A lone zero block at %s'
+ 'A lone zero block at %s'
-Keywords applicable for `tar --create'
+Keywords applicable for 'tar --create'
--------------------------------------
cachedir
- `%s: contains a cache directory tag %s; %s'
-
+ '%s: contains a cache directory tag %s; %s'
file-shrank
- `%s: File shrank by %s bytes; padding with zeros'
-
+ '%s: File shrank by %s bytes; padding with zeros'
xdev
- `%s: file is on a different filesystem; not dumped'
-
+ '%s: file is on a different filesystem; not dumped'
file-ignored
- `%s: Unknown file type; file ignored'
- `%s: socket ignored'
- `%s: door ignored'
-
+ '%s: Unknown file type; file ignored'
+ '%s: socket ignored'
+ '%s: door ignored'
file-unchanged
- `%s: file is unchanged; not dumped'
-
+ '%s: file is unchanged; not dumped'
ignore-archive
- `%s: file is the archive; not dumped'
-
+ '%s: file is the archive; not dumped'
file-removed
- `%s: File removed before we read it'
-
+ '%s: File removed before we read it'
file-changed
- `%s: file changed as we read it'
+ '%s: file changed as we read it'
-Keywords applicable for `tar --extract'
+Keywords applicable for 'tar --extract'
---------------------------------------
+existing-file
+ '%s: skipping existing file'
timestamp
- `%s: implausibly old time stamp %s'
- `%s: time stamp %s is %s s in the future'
-
+ '%s: implausibly old time stamp %s'
+ '%s: time stamp %s is %s s in the future'
contiguous-cast
- `Extracting contiguous files as regular files'
-
+ 'Extracting contiguous files as regular files'
symlink-cast
- `Attempting extraction of symbolic links as hard links'
-
+ 'Attempting extraction of symbolic links as hard links'
unknown-cast
- `%s: Unknown file type '%c', extracted as normal file'
-
+ '%s: Unknown file type '%c', extracted as normal file'
ignore-newer
- `Current %s is newer or same age'
-
+ 'Current %s is newer or same age'
unknown-keyword
- `Ignoring unknown extended header keyword '%s''
-
+ 'Ignoring unknown extended header keyword '%s''
decompress-program
Controls verbose description of failures occurring when trying to
run alternative decompressor programs (*note alternative
decompression programs::). This warning is disabled by default
- (unless `--verbose' is used). A common example of what you can get
+ (unless '--verbose' is used). A common example of what you can get
when using this warning is:
$ tar --warning=decompress-program -x -f archive.Z
tar (child): cannot run compress: No such file or directory
tar (child): trying gzip
- This means that `tar' first tried to decompress `archive.Z' using
- `compress', and, when that failed, switched to `gzip'.
-
+ This means that 'tar' first tried to decompress 'archive.Z' using
+ 'compress', and, when that failed, switched to 'gzip'.
record-size
- `Record size = %lu blocks'
+ 'Record size = %lu blocks'
Keywords controlling incremental extraction:
--------------------------------------------
rename-directory
- `%s: Directory has been renamed from %s'
- `%s: Directory has been renamed'
-
+ '%s: Directory has been renamed from %s'
+ '%s: Directory has been renamed'
new-directory
- `%s: Directory is new'
-
+ '%s: Directory is new'
xdev
- `%s: directory is on a different device: not purging'
-
+ '%s: directory is on a different device: not purging'
bad-dumpdir
- `Malformed dumpdir: 'X' never used'
+ 'Malformed dumpdir: 'X' never used'
\1f
File: tar.info, Node: interactive, Next: external, Prev: warnings, Up: tar invocation
3.10 Asking for Confirmation During Operations
==============================================
-Typically, `tar' carries out a command without stopping for further
+Typically, 'tar' carries out a command without stopping for further
instructions. In some situations however, you may want to exclude some
files and archive members from the operation (for instance if disk or
storage space is tight). You can do this by excluding certain files
automatically (*note Choosing::), or by performing an operation
-interactively, using the `--interactive' (`-w') option. `tar' also
-accepts `--confirmation' for this option.
+interactively, using the '--interactive' ('-w') option. 'tar' also
+accepts '--confirmation' for this option.
- When the `--interactive' (`-w') option is specified, before reading,
-writing, or deleting files, `tar' first prints a message for each such
+ When the '--interactive' ('-w') option is specified, before reading,
+writing, or deleting files, 'tar' first prints a message for each such
file, telling what operation it intends to take, then asks for
confirmation on the terminal. The actions which require confirmation
include adding a file to the archive, extracting a file from the
archive, deleting a file from the archive, and deleting a file from
disk. To confirm the action, you must type a line of input beginning
-with `y'. If your input line begins with anything other than `y',
-`tar' skips that file.
+with 'y'. If your input line begins with anything other than 'y', 'tar'
+skips that file.
- If `tar' is reading the archive from the standard input, `tar' opens
-the file `/dev/tty' to support the interactive communications.
+ If 'tar' is reading the archive from the standard input, 'tar' opens
+the file '/dev/tty' to support the interactive communications.
Verbose output is normally sent to standard output, separate from
other error messages. However, if the archive is produced directly on
-standard output, then verbose output is mixed with errors on `stderr'.
+standard output, then verbose output is mixed with errors on 'stderr'.
Producing the archive on standard output may be used as a way to avoid
using disk space, when the archive is soon to be consumed by another
process reading it, say. Some people felt the need of producing an
-archive on stdout, still willing to segregate between verbose output
-and error output. A possible approach would be using a named pipe to
+archive on stdout, still willing to segregate between verbose output and
+error output. A possible approach would be using a named pipe to
receive the archive, and having the consumer process to read from that
named pipe. This has the advantage of letting standard output free to
receive verbose output, all separate from errors.
3.11 Running External Commands
==============================
-Certain GNU `tar' operations imply running external commands that you
+Certain GNU 'tar' operations imply running external commands that you
supply on the command line. One of such operations is checkpointing,
described above (*note checkpoint exec::). Another example of this
-feature is the `-I' option, which allows you to supply the program to
+feature is the '-I' option, which allows you to supply the program to
use for compressing or decompressing the archive (*note
use-compress-program::).
- Whenever such operation is requested, `tar' first splits the
-supplied command into words much like the shell does. It then treats
-the first word as the name of the program or the shell script to execute
-and the rest of words as its command line arguments. The program,
-unless given as an absolute file name, is searched in the shell's
-`PATH'.
+ Whenever such operation is requested, 'tar' first splits the supplied
+command into words much like the shell does. It then treats the first
+word as the name of the program or the shell script to execute and the
+rest of words as its command line arguments. The program, unless given
+as an absolute file name, is searched in the shell's 'PATH'.
Any additional information is normally supplied to external commands
in environment variables, specific to each particular operation. For
-example, the `--checkpoint-action=exec' option, defines the
-`TAR_ARCHIVE' variable to the name of the archive being worked upon.
+example, the '--checkpoint-action=exec' option, defines the
+'TAR_ARCHIVE' variable to the name of the archive being worked upon.
You can, should the need be, use these variables in the command line of
the external command. For example:
$ tar -x -f archive.tar \
- --checkpoint=exec='printf "%04d in %32s\r" $TAR_CHECKPOINT $TAR_ARCHIVE'
+ --checkpoint-action=exec='printf "%04d in %32s\r" $TAR_CHECKPOINT $TAR_ARCHIVE'
This command prints for each checkpoint its number and the name of the
archive, using the same output line on the screen.
Notice the use of single quotes to prevent variable names from being
-expanded by the shell when invoking `tar'.
+expanded by the shell when invoking 'tar'.
\1f
File: tar.info, Node: operations, Next: Backups, Prev: tar invocation, Up: Top
-4 GNU `tar' Operations
+4 GNU 'tar' Operations
**********************
* Menu:
\1f
File: tar.info, Node: Basic tar, Next: Advanced tar, Up: operations
-4.1 Basic GNU `tar' Operations
+4.1 Basic GNU 'tar' Operations
==============================
-The basic `tar' operations, `--create' (`-c'), `--list' (`-t') and
-`--extract' (`--get', `-x'), are currently presented and described in
+The basic 'tar' operations, '--create' ('-c'), '--list' ('-t') and
+'--extract' ('--get', '-x'), are currently presented and described in
the tutorial chapter of this manual. This section provides some
complementary notes for these operations.
-`--create'
-`-c'
+'--create'
+'-c'
+
Creating an empty archive would have some kind of elegance. One
- can initialize an empty archive and later use `--append' (`-r')
- for adding all members. Some applications would not welcome
- making an exception in the way of adding the first archive member.
- On the other hand, many people reported that it is dangerously too
- easy for `tar' to destroy a magnetic tape with an empty
- archive(1). The two most common errors are:
-
- 1. Mistakingly using `create' instead of `extract', when the
+ can initialize an empty archive and later use '--append' ('-r') for
+ adding all members. Some applications would not welcome making an
+ exception in the way of adding the first archive member. On the
+ other hand, many people reported that it is dangerously too easy
+ for 'tar' to destroy a magnetic tape with an empty archive(1). The
+ two most common errors are:
+
+ 1. Mistakingly using 'create' instead of 'extract', when the
intent was to extract the full contents of an archive. This
- error is likely: keys `c' and `x' are right next to each
- other on the QWERTY keyboard. Instead of being unpacked, the
+ error is likely: keys 'c' and 'x' are right next to each other
+ on the QWERTY keyboard. Instead of being unpacked, the
archive then gets wholly destroyed. When users speak about
"exploding" an archive, they usually mean something else :-).
- 2. Forgetting the argument to `file', when the intent was to
+ 2. Forgetting the argument to 'file', when the intent was to
create an archive with a single file in it. This error is
- likely because a tired user can easily add the `f' key to the
- cluster of option letters, by the mere force of habit,
- without realizing the full consequence of doing so. The
- usual consequence is that the single file, which was meant to
- be saved, is rather destroyed.
+ likely because a tired user can easily add the 'f' key to the
+ cluster of option letters, by the mere force of habit, without
+ realizing the full consequence of doing so. The usual
+ consequence is that the single file, which was meant to be
+ saved, is rather destroyed.
So, recognizing the likelihood and the catastrophic nature of these
- errors, GNU `tar' now takes some distance from elegance, and
- cowardly refuses to create an archive when `--create' option is
- given, there are no arguments besides options, and `--files-from'
- (`-T') option is _not_ used. To get around the cautiousness of
- GNU `tar' and nevertheless create an archive with nothing in it,
- one may still use, as the value for the `--files-from' option, a
- file with no names in it, as shown in the following commands:
+ errors, GNU 'tar' now takes some distance from elegance, and
+ cowardly refuses to create an archive when '--create' option is
+ given, there are no arguments besides options, and '--files-from'
+ ('-T') option is _not_ used. To get around the cautiousness of GNU
+ 'tar' and nevertheless create an archive with nothing in it, one
+ may still use, as the value for the '--files-from' option, a file
+ with no names in it, as shown in the following commands:
tar --create --file=empty-archive.tar --files-from=/dev/null
tar -cf empty-archive.tar -T /dev/null
-`--extract'
-`--get'
-`-x'
- A socket is stored, within a GNU `tar' archive, as a pipe.
+'--extract'
+'--get'
+'-x'
+
+ A socket is stored, within a GNU 'tar' archive, as a pipe.
+
+'--list (-t)'
-``--list' (`-t')'
- GNU `tar' now shows dates as `1996-08-30', while it used to show
- them as `Aug 30 1996'. Preferably, people should get used to ISO
+ GNU 'tar' now shows dates as '1996-08-30', while it used to show
+ them as 'Aug 30 1996'. Preferably, people should get used to ISO
8601 dates. Local American dates should be made available again
with full date localization support, once ready. In the meantime,
programs not being localizable for dates should prefer
international dates, that's really the way to go.
- Look up `http://www.cl.cam.ac.uk/~mgk25/iso-time.html' if you are
+ Look up <http://www.cl.cam.ac.uk/~mgk25/iso-time.html> if you are
curious, it contains a detailed explanation of the ISO 8601
standard.
-
---------- Footnotes ----------
- (1) This is well described in `Unix-haters Handbook', by Simson
+ (1) This is well described in 'Unix-haters Handbook', by Simson
Garfinkel, Daniel Weise & Steven Strassmann, IDG Books, ISBN
1-56884-203-1.
\1f
File: tar.info, Node: Advanced tar, Next: create options, Prev: Basic tar, Up: operations
-4.2 Advanced GNU `tar' Operations
+4.2 Advanced GNU 'tar' Operations
=================================
-Now that you have learned the basics of using GNU `tar', you may want
-to learn about further ways in which `tar' can help you.
+Now that you have learned the basics of using GNU 'tar', you may want to
+learn about further ways in which 'tar' can help you.
This chapter presents five, more advanced operations which you
probably won't use on a daily basis, but which serve more specialized
functions. We also explain the different styles of options and why you
-might want to use one or another, or a combination of them in your `tar'
+might want to use one or another, or a combination of them in your 'tar'
commands. Additionally, this chapter includes options which allow you
-to define the output from `tar' more carefully, and provide help and
+to define the output from 'tar' more carefully, and provide help and
error correction in special circumstances.
* Menu:
\1f
File: tar.info, Node: Operations, Next: append, Up: Advanced tar
-4.2.1 The Five Advanced `tar' Operations
+4.2.1 The Five Advanced 'tar' Operations
----------------------------------------
In the last chapter, you learned about the first three operations to
-`tar'. This chapter presents the remaining five operations to `tar':
-`--append', `--update', `--concatenate', `--delete', and `--compare'.
+'tar'. This chapter presents the remaining five operations to 'tar':
+'--append', '--update', '--concatenate', '--delete', and '--compare'.
You are not likely to use these operations as frequently as those
covered in the last chapter; however, since they perform specialized
functions, they are quite useful when you do need to use them. We will
-give examples using the same directory and files that you created in
-the last chapter. As you may recall, the directory is called
-`practice', the files are `jazz', `blues', `folk', and the two archive
-files you created are `collection.tar' and `music.tar'.
+give examples using the same directory and files that you created in the
+last chapter. As you may recall, the directory is called 'practice',
+the files are 'jazz', 'blues', 'folk', and the two archive files you
+created are 'collection.tar' and 'music.tar'.
- We will also use the archive files `afiles.tar' and `bfiles.tar'.
-The archive `afiles.tar' contains the members `apple', `angst', and
-`aspic'; `bfiles.tar' contains the members `./birds', `baboon', and
-`./box'.
+ We will also use the archive files 'afiles.tar' and 'bfiles.tar'.
+The archive 'afiles.tar' contains the members 'apple', 'angst', and
+'aspic'; 'bfiles.tar' contains the members './birds', 'baboon', and
+'./box'.
Unless we state otherwise, all practicing you do and examples you
-follow in this chapter will take place in the `practice' directory that
+follow in this chapter will take place in the 'practice' directory that
you created in the previous chapter; see *note prepare for examples::.
(Below in this section, we will remind you of the state of the examples
where the last chapter left them.)
The five operations that we will cover in this chapter are:
-`--append'
-`-r'
+'--append'
+'-r'
Add new entries to an archive that already exists.
-
-`--update'
-`-u'
- Add more recent copies of archive members to the end of an
- archive, if they exist.
-
-`--concatenate'
-`--catenate'
-`-A'
+'--update'
+'-u'
+ Add more recent copies of archive members to the end of an archive,
+ if they exist.
+'--concatenate'
+'--catenate'
+'-A'
Add one or more pre-existing archives to the end of another
archive.
-
-`--delete'
+'--delete'
Delete items from an archive (does not work on tapes).
-
-`--compare'
-`--diff'
-`-d'
+'--compare'
+'--diff'
+'-d'
Compare archive members to their counterparts in the file system.
\1f
File: tar.info, Node: append, Next: update, Prev: Operations, Up: Advanced tar
-4.2.2 How to Add Files to Existing Archives: `--append'
+4.2.2 How to Add Files to Existing Archives: '--append'
-------------------------------------------------------
If you want to add files to an existing archive, you don't need to
-create a new archive; you can use `--append' (`-r'). The archive must
-already exist in order to use `--append'. (A related operation is the
-`--update' operation; you can use this to add newer versions of archive
+create a new archive; you can use '--append' ('-r'). The archive must
+already exist in order to use '--append'. (A related operation is the
+'--update' operation; you can use this to add newer versions of archive
members to an existing archive. To learn how to do this with
-`--update', *note update::.)
+'--update', *note update::.)
- If you use `--append' to add a file that has the same name as an
+ If you use '--append' to add a file that has the same name as an
archive member to an archive containing that archive member, then the
old member is not deleted. What does happen, however, is somewhat
-complex. `tar' _allows_ you to have infinite number of files with the
+complex. 'tar' _allows_ you to have infinite number of files with the
same name. Some operations treat these same-named members no
differently than any other set of archive members: for example, if you
-view an archive with `--list' (`-t'), you will see all of those members
+view an archive with '--list' ('-t'), you will see all of those members
listed, with their data modification times, owners, etc.
Other operations don't deal with these members as perfectly as you
-might prefer; if you were to use `--extract' to extract the archive,
+might prefer; if you were to use '--extract' to extract the archive,
only the most recently added copy of a member with the same name as
other members would end up in the working directory. This is because
-`--extract' extracts an archive in the order the members appeared in
-the archive; the most recently archived members will be extracted last.
-Additionally, an extracted member will _replace_ a file of the same
-name which existed in the directory already, and `tar' will not prompt
-you about this(1). Thus, only the most recently archived member will
-end up being extracted, as it will replace the one extracted before it,
-and so on.
+'--extract' extracts an archive in the order the members appeared in the
+archive; the most recently archived members will be extracted last.
+Additionally, an extracted member will _replace_ a file of the same name
+which existed in the directory already, and 'tar' will not prompt you
+about this(1). Thus, only the most recently archived member will end up
+being extracted, as it will replace the one extracted before it, and so
+on.
There exists a special option that allows you to get around this
-behavior and extract (or list) only a particular copy of the file.
-This is `--occurrence' option. If you run `tar' with this option, it
-will extract only the first copy of the file. You may also give this
-option an argument specifying the number of copy to be extracted.
-Thus, for example if the archive `archive.tar' contained three copies
-of file `myfile', then the command
+behavior and extract (or list) only a particular copy of the file. This
+is '--occurrence' option. If you run 'tar' with this option, it will
+extract only the first copy of the file. You may also give this option
+an argument specifying the number of copy to be extracted. Thus, for
+example if the archive 'archive.tar' contained three copies of file
+'myfile', then the command
tar --extract --file archive.tar --occurrence=2 myfile
-would extract only the second copy. *Note --occurrence: Option
-Summary, for the description of `--occurrence' option.
+would extract only the second copy. *Note --occurrence: Option Summary,
+for the description of '--occurrence' option.
- If you want to replace an archive member, use `--delete' to delete
-the member you want to remove from the archive, and then use `--append'
+ If you want to replace an archive member, use '--delete' to delete
+the member you want to remove from the archive, and then use '--append'
to add the member you want to be in the archive. Note that you can not
change the order of the archive; the most recently added member will
-still appear last. In this sense, you cannot truly "replace" one
-member with another. (Replacing one member with another will not work
-on certain types of media, such as tapes; see *note delete:: and *note
+still appear last. In this sense, you cannot truly "replace" one member
+with another. (Replacing one member with another will not work on
+certain types of media, such as tapes; see *note delete:: and *note
Media::, for more information.)
* Menu:
---------- Footnotes ----------
- (1) Unless you give it `--keep-old-files' (or `--skip-old-files')
+ (1) Unless you give it '--keep-old-files' (or '--skip-old-files')
option, or the disk copy is newer than the one in the archive and you
-invoke `tar' with `--keep-newer-files' option.
+invoke 'tar' with '--keep-newer-files' option.
\1f
File: tar.info, Node: appending files, Next: multiple, Up: append
.....................................
The simplest way to add a file to an already existing archive is the
-`--append' (`-r') operation, which writes specified files into the
+'--append' ('-r') operation, which writes specified files into the
archive whether or not they are already among the archived files.
- When you use `--append', you _must_ specify file name arguments, as
+ When you use '--append', you _must_ specify file name arguments, as
there is no default. If you specify a file that already exists in the
archive, another copy of the file will be added to the end of the
archive. As with other operations, the member names of the newly added
-files will be exactly the same as their names given on the command
-line. The `--verbose' (`-v') option will print out the names of the
-files as they are written into the archive.
+files will be exactly the same as their names given on the command line.
+The '--verbose' ('-v') option will print out the names of the files as
+they are written into the archive.
- `--append' cannot be performed on some tape drives, unfortunately,
+ '--append' cannot be performed on some tape drives, unfortunately,
due to deficiencies in the formats those tape drives use. The archive
-must be a valid `tar' archive, or else the results of using this
+must be a valid 'tar' archive, or else the results of using this
operation will be unpredictable. *Note Media::.
- To demonstrate using `--append' to add a file to an archive, create
-a file called `rock' in the `practice' directory. Make sure you are in
-the `practice' directory. Then, run the following `tar' command to add
-`rock' to `collection.tar':
+ To demonstrate using '--append' to add a file to an archive, create a
+file called 'rock' in the 'practice' directory. Make sure you are in
+the 'practice' directory. Then, run the following 'tar' command to add
+'rock' to 'collection.tar':
$ tar --append --file=collection.tar rock
-If you now use the `--list' (`-t') operation, you will see that `rock'
+If you now use the '--list' ('-t') operation, you will see that 'rock'
has been added to the archive:
$ tar --list --file=collection.tar
4.2.2.2 Multiple Members with the Same Name
...........................................
-You can use `--append' (`-r') to add copies of files which have been
+You can use '--append' ('-r') to add copies of files which have been
updated since the archive was created. (However, we do not recommend
-doing this since there is another `tar' option called `--update'; *Note
-update::, for more information. We describe this use of `--append'
-here for the sake of completeness.) When you extract the archive, the
-older version will be effectively lost. This works because files are
+doing this since there is another 'tar' option called '--update'; *Note
+update::, for more information. We describe this use of '--append' here
+for the sake of completeness.) When you extract the archive, the older
+version will be effectively lost. This works because files are
extracted from an archive in the order in which they were archived.
Thus, when the archive is extracted, a file archived later in time will
replace a file of the same name which was archived earlier, even though
the older version of the file will remain in the archive unless you
delete all versions of the file.
- Supposing you change the file `blues' and then append the changed
-version to `collection.tar'. As you saw above, the original `blues' is
-in the archive `collection.tar'. If you change the file and append the
+ Supposing you change the file 'blues' and then append the changed
+version to 'collection.tar'. As you saw above, the original 'blues' is
+in the archive 'collection.tar'. If you change the file and append the
new version of the file to the archive, there will be two copies in the
archive. When you extract the archive, the older version of the file
will be extracted first, and then replaced by the newer version when it
is extracted.
- You can append the new, changed copy of the file `blues' to the
+ You can append the new, changed copy of the file 'blues' to the
archive in this way:
$ tar --append --verbose --file=collection.tar blues
blues
-Because you specified the `--verbose' option, `tar' has printed the
-name of the file being appended as it was acted on. Now list the
-contents of the archive:
+Because you specified the '--verbose' option, 'tar' has printed the name
+of the file being appended as it was acted on. Now list the contents of
+the archive:
$ tar --list --verbose --file=collection.tar
-rw-r--r-- me/user 28 1996-10-18 16:31 jazz
-rw-r--r-- me/user 20 1996-09-23 16:44 rock
-rw-r--r-- me/user 58 1996-10-24 18:30 blues
-The newest version of `blues' is now at the end of the archive (note
-the different creation dates and file sizes). If you extract the
-archive, the older version of the file `blues' will be replaced by the
-newer version. You can confirm this by extracting the archive and
-running `ls' on the directory.
+The newest version of 'blues' is now at the end of the archive (note the
+different creation dates and file sizes). If you extract the archive,
+the older version of the file 'blues' will be replaced by the newer
+version. You can confirm this by extracting the archive and running
+'ls' on the directory.
- If you wish to extract the first occurrence of the file `blues' from
-the archive, use `--occurrence' option, as shown in the following
+ If you wish to extract the first occurrence of the file 'blues' from
+the archive, use '--occurrence' option, as shown in the following
example:
$ tar --extract -vv --occurrence --file=collection.tar blues
-rw-r--r-- me/user 21 1996-09-23 16:44 blues
- *Note Writing::, for more information on `--extract' and see *note
--occurrence: Option Summary, for a description of `--occurrence' option.
+ *Note Writing::, for more information on '--extract' and see *note
+-occurrence: Option Summary, for a description of '--occurrence' option.
\1f
File: tar.info, Node: update, Next: concatenate, Prev: append, Up: Advanced tar
4.2.3 Updating an Archive
-------------------------
-In the previous section, you learned how to use `--append' to add a
-file to an existing archive. A related operation is `--update' (`-u').
-The `--update' operation updates a `tar' archive by comparing the date
-of the specified archive members against the date of the file with the
-same name. If the file has been modified more recently than the
-archive member, then the newer version of the file is added to the
-archive (as with `--append').
+In the previous section, you learned how to use '--append' to add a file
+to an existing archive. A related operation is '--update' ('-u'). The
+'--update' operation updates a 'tar' archive by comparing the date of
+the specified archive members against the date of the file with the same
+name. If the file has been modified more recently than the archive
+member, then the newer version of the file is added to the archive (as
+with '--append').
- Unfortunately, you cannot use `--update' with magnetic tape drives.
+ Unfortunately, you cannot use '--update' with magnetic tape drives.
The operation will fail.
- Both `--update' and `--append' work by adding to the end of the
+ Both '--update' and '--append' work by adding to the end of the
archive. When you extract a file from the archive, only the version
stored last will wind up in the file system, unless you use the
-`--backup' option. *Note multiple::, for a detailed discussion.
+'--backup' option. *Note multiple::, for a detailed discussion.
* Menu:
\1f
File: tar.info, Node: how to update, Up: update
-4.2.3.1 How to Update an Archive Using `--update'
+4.2.3.1 How to Update an Archive Using '--update'
.................................................
-You must use file name arguments with the `--update' (`-u') operation.
-If you don't specify any files, `tar' won't act on any files and won't
+You must use file name arguments with the '--update' ('-u') operation.
+If you don't specify any files, 'tar' won't act on any files and won't
tell you that it didn't do anything (which may end up confusing you).
- To see the `--update' option at work, create a new file,
-`classical', in your practice directory, and some extra text to the
-file `blues', using any text editor. Then invoke `tar' with the
-`update' operation and the `--verbose' (`-v') option specified, using
-the names of all the files in the `practice' directory as file name
-arguments:
+ To see the '--update' option at work, create a new file, 'classical',
+in your practice directory, and some extra text to the file 'blues',
+using any text editor. Then invoke 'tar' with the 'update' operation
+and the '--verbose' ('-v') option specified, using the names of all the
+files in the 'practice' directory as file name arguments:
$ tar --update -v -f collection.tar blues folk rock classical
blues
classical
$
-Because we have specified verbose mode, `tar' prints out the names of
+Because we have specified verbose mode, 'tar' prints out the names of
the files it is working on, which in this case are the names of the
-files that needed to be updated. If you run `tar --list' and look at
-the archive, you will see `blues' and `classical' at its end. There
-will be a total of two versions of the member `blues'; the one at the
+files that needed to be updated. If you run 'tar --list' and look at
+the archive, you will see 'blues' and 'classical' at its end. There
+will be a total of two versions of the member 'blues'; the one at the
end will be newer and larger, since you added text before updating it.
- The reason `tar' does not overwrite the older file when updating it
+ The reason 'tar' does not overwrite the older file when updating it
is because writing to the middle of a section of tape is a difficult
process. Tapes are not designed to go backward. *Note Media::, for
more information about tapes.
- `--update' (`-u') is not suitable for performing backups for two
+ '--update' ('-u') is not suitable for performing backups for two
reasons: it does not change directory content entries, and it lengthens
-the archive every time it is used. The GNU `tar' options intended
+the archive every time it is used. The GNU 'tar' options intended
specifically for backups are more efficient. If you need to run
backups, please consult *note Backups::.
\1f
File: tar.info, Node: concatenate, Next: delete, Prev: update, Up: Advanced tar
-4.2.4 Combining Archives with `--concatenate'
+4.2.4 Combining Archives with '--concatenate'
---------------------------------------------
Sometimes it may be convenient to add a second archive onto the end of
an archive rather than adding individual files to the archive. To add
one or more archives to the end of another archive, you should use the
-`--concatenate' (`--catenate', `-A') operation.
+'--concatenate' ('--catenate', '-A') operation.
- To use `--concatenate', give the first archive with `--file' option
+ To use '--concatenate', give the first archive with '--file' option
and name the rest of archives to be concatenated on the command line.
The members, and their member names, will be copied verbatim from those
archives to the first one(1). The new, concatenated archive will be
-called by the same name as the one given with the `--file' option. As
-usual, if you omit `--file', `tar' will use the value of the environment
-variable `TAPE', or, if this has not been set, the default archive name.
+called by the same name as the one given with the '--file' option. As
+usual, if you omit '--file', 'tar' will use the value of the environment
+variable 'TAPE', or, if this has not been set, the default archive name.
- To demonstrate how `--concatenate' works, create two small archives
-called `bluesrock.tar' and `folkjazz.tar', using the relevant files
-from `practice':
+ To demonstrate how '--concatenate' works, create two small archives
+called 'bluesrock.tar' and 'folkjazz.tar', using the relevant files from
+'practice':
$ tar -cvf bluesrock.tar blues rock
blues
folk
jazz
-If you like, You can run `tar --list' to make sure the archives contain
+If you like, You can run 'tar --list' to make sure the archives contain
what they are supposed to:
$ tar -tvf bluesrock.tar
-rw-r--r-- melissa/user 20 1996-09-23 16:44 folk
-rw-r--r-- melissa/user 65 1997-01-30 14:15 jazz
- We can concatenate these two archives with `tar':
+ We can concatenate these two archives with 'tar':
$ cd ..
$ tar --concatenate --file=bluesrock.tar jazzfolk.tar
- If you now list the contents of the `bluesrock.tar', you will see
-that now it also contains the archive members of `jazzfolk.tar':
+ If you now list the contents of the 'bluesrock.tar', you will see
+that now it also contains the archive members of 'jazzfolk.tar':
$ tar --list --file=bluesrock.tar
blues
folk
jazz
- When you use `--concatenate', the source and target archives must
+ When you use '--concatenate', the source and target archives must
already exist and must have been created using compatible format
-parameters. Notice, that `tar' does not check whether the archives it
+parameters. Notice, that 'tar' does not check whether the archives it
concatenates have compatible formats, it does not even check if the
files are really tar archives.
- Like `--append' (`-r'), this operation cannot be performed on some
+ Like '--append' ('-r'), this operation cannot be performed on some
tape drives, due to deficiencies in the formats those tape drives use.
- It may seem more intuitive to you to want or try to use `cat' to
-concatenate two archives instead of using the `--concatenate'
-operation; after all, `cat' is the utility for combining files.
+ It may seem more intuitive to you to want or try to use 'cat' to
+concatenate two archives instead of using the '--concatenate' operation;
+after all, 'cat' is the utility for combining files.
- However, `tar' archives incorporate an end-of-file marker which must
+ However, 'tar' archives incorporate an end-of-file marker which must
be removed if the concatenated archives are to be read properly as one
-archive. `--concatenate' removes the end-of-archive marker from the
-target archive before each new archive is appended. If you use `cat'
-to combine the archives, the result will not be a valid `tar' format
+archive. '--concatenate' removes the end-of-archive marker from the
+target archive before each new archive is appended. If you use 'cat' to
+combine the archives, the result will not be a valid 'tar' format
archive. If you need to retrieve files from an archive that was added
-to using the `cat' utility, use the `--ignore-zeros' (`-i') option.
+to using the 'cat' utility, use the '--ignore-zeros' ('-i') option.
*Note Ignore Zeros::, for further information on dealing with archives
-improperly combined using the `cat' shell utility.
+improperly combined using the 'cat' shell utility.
---------- Footnotes ----------
\1f
File: tar.info, Node: delete, Next: compare, Prev: concatenate, Up: Advanced tar
-4.2.5 Removing Archive Members Using `--delete'
+4.2.5 Removing Archive Members Using '--delete'
-----------------------------------------------
-You can remove members from an archive by using the `--delete' option.
-Specify the name of the archive with `--file' (`-f') and then specify
+You can remove members from an archive by using the '--delete' option.
+Specify the name of the archive with '--file' ('-f') and then specify
the names of the members to be deleted; if you list no member names,
-nothing will be deleted. The `--verbose' option will cause `tar' to
-print the names of the members as they are deleted. As with
-`--extract', you must give the exact member names when using `tar
---delete'. `--delete' will remove all versions of the named file from
-the archive. The `--delete' operation can run very slowly.
-
- Unlike other operations, `--delete' has no short form.
-
- This operation will rewrite the archive. You can only use
-`--delete' on an archive if the archive device allows you to write to
-any point on the media, such as a disk; because of this, it does not
-work on magnetic tapes. Do not try to delete an archive member from a
-magnetic tape; the action will not succeed, and you will be likely to
-scramble the archive and damage your tape. There is no safe way
-(except by completely re-writing the archive) to delete files from most
-kinds of magnetic tape. *Note Media::.
-
- To delete all versions of the file `blues' from the archive
-`collection.tar' in the `practice' directory, make sure you are in that
+nothing will be deleted. The '--verbose' option will cause 'tar' to
+print the names of the members as they are deleted. As with
+'--extract', you must give the exact member names when using 'tar
+--delete'. '--delete' will remove all versions of the named file from
+the archive. The '--delete' operation can run very slowly.
+
+ Unlike other operations, '--delete' has no short form.
+
+ This operation will rewrite the archive. You can only use '--delete'
+on an archive if the archive device allows you to write to any point on
+the media, such as a disk; because of this, it does not work on magnetic
+tapes. Do not try to delete an archive member from a magnetic tape; the
+action will not succeed, and you will be likely to scramble the archive
+and damage your tape. There is no safe way (except by completely
+re-writing the archive) to delete files from most kinds of magnetic
+tape. *Note Media::.
+
+ To delete all versions of the file 'blues' from the archive
+'collection.tar' in the 'practice' directory, make sure you are in that
directory, and then,
$ tar --list --file=collection.tar
jazz
rock
- The `--delete' option has been reported to work properly when `tar'
-acts as a filter from `stdin' to `stdout'.
+ The '--delete' option has been reported to work properly when 'tar'
+acts as a filter from 'stdin' to 'stdout'.
\1f
File: tar.info, Node: compare, Prev: delete, Up: Advanced tar
4.2.6 Comparing Archive Members with the File System
----------------------------------------------------
-The `--compare' (`-d'), or `--diff' operation compares specified
-archive members against files with the same names, and then reports
-differences in file size, mode, owner, modification date and contents.
-You should _only_ specify archive member names, not file names. If you
-do not name any members, then `tar' will compare the entire archive.
-If a file is represented in the archive but does not exist in the file
-system, `tar' reports a difference.
+The '--compare' ('-d'), or '--diff' operation compares specified archive
+members against files with the same names, and then reports differences
+in file size, mode, owner, modification date and contents. You should
+_only_ specify archive member names, not file names. If you do not name
+any members, then 'tar' will compare the entire archive. If a file is
+represented in the archive but does not exist in the file system, 'tar'
+reports a difference.
You have to specify the record size of the archive when modifying an
archive with a non-default record size.
- `tar' ignores files in the file system that do not have
-corresponding members in the archive.
+ 'tar' ignores files in the file system that do not have corresponding
+members in the archive.
- The following example compares the archive members `rock', `blues'
-and `funk' in the archive `bluesrock.tar' with files of the same name
-in the file system. (Note that there is no file, `funk'; `tar' will
-report an error message.)
+ The following example compares the archive members 'rock', 'blues'
+and 'funk' in the archive 'bluesrock.tar' with files of the same name in
+the file system. (Note that there is no file, 'funk'; 'tar' will report
+an error message.)
$ tar --compare --file=bluesrock.tar rock blues funk
rock
blues
tar: funk not found in archive
- The spirit behind the `--compare' (`--diff', `-d') option is to
-check whether the archive represents the current state of files on
-disk, more than validating the integrity of the archive media. For
-this latter goal, see *note verify::.
+ The spirit behind the '--compare' ('--diff', '-d') option is to check
+whether the archive represents the current state of files on disk, more
+than validating the integrity of the archive media. For this latter
+goal, see *note verify::.
\1f
File: tar.info, Node: create options, Next: extract options, Prev: Advanced tar, Up: operations
-4.3 Options Used by `--create'
+4.3 Options Used by '--create'
==============================
-The previous chapter described the basics of how to use `--create'
-(`-c') to create an archive from a set of files. *Note create::. This
-section described advanced options to be used with `--create'.
+The previous chapter described the basics of how to use '--create'
+('-c') to create an archive from a set of files. *Note create::. This
+section described advanced options to be used with '--create'.
* Menu:
* override:: Overriding File Metadata.
+* Extended File Attributes::
* Ignore Failed Read::
\1f
-File: tar.info, Node: override, Next: Ignore Failed Read, Up: create options
+File: tar.info, Node: override, Next: Extended File Attributes, Up: create options
4.3.1 Overriding File Metadata
------------------------------
-As described above, a `tar' archive keeps, for each member it contains,
+As described above, a 'tar' archive keeps, for each member it contains,
its "metadata", such as modification time, mode and ownership of the
-file. GNU `tar' allows to replace these data with other values when
+file. GNU 'tar' allows to replace these data with other values when
adding files to the archive. The options described in this section
affect creation of archives of any type. For POSIX archives, see also
*note PAX keywords::, for additional ways of controlling metadata,
stored in the archive.
-`--mode=PERMISSIONS'
- When adding files to an archive, `tar' will use PERMISSIONS for
- the archive members, rather than the permissions from the files.
+'--mode=PERMISSIONS'
+
+ When adding files to an archive, 'tar' will use PERMISSIONS for the
+ archive members, rather than the permissions from the files.
PERMISSIONS can be specified either as an octal number or as
- symbolic permissions, like with `chmod' (*Note Permissions:
+ symbolic permissions, like with 'chmod' (*Note Permissions:
(fileutils)File permissions. This reference also has useful
information for those not being overly familiar with the UNIX
permission system). Using latter syntax allows for more
- flexibility. For example, the value `a+rw' adds read and write
+ flexibility. For example, the value 'a+rw' adds read and write
permissions for everybody, while retaining executable bits on
directories or on any other file already marked as executable:
$ tar -c -f archive.tar --mode='a+rw' .
-`--mtime=DATE'
- When adding files to an archive, `tar' will use DATE as the
+'--mtime=DATE'
+
+ When adding files to an archive, 'tar' will use DATE as the
modification time of members when creating archives, instead of
- their actual modification times. The argument DATE can be either
- a textual date representation in almost arbitrary format (*note
- Date input formats::) or a name of an existing file, starting with
- `/' or `.'. In the latter case, the modification time of that
- file will be used.
+ their actual modification times. The argument DATE can be either a
+ textual date representation in almost arbitrary format (*note Date
+ input formats::) or a name of an existing file, starting with '/'
+ or '.'. In the latter case, the modification time of that file
+ will be used.
The following example will set the modification date to 00:00:00,
January 1, 1970:
$ tar -c -f archive.tar --mtime='1970-01-01' .
- When used with `--verbose' (*note verbose tutorial::) GNU `tar'
+ When used with '--verbose' (*note verbose tutorial::) GNU 'tar'
will try to convert the specified date back to its textual
- representation and compare it with the one given with `--mtime'
- options. If the two dates differ, `tar' will print a warning
+ representation and compare it with the one given with '--mtime'
+ options. If the two dates differ, 'tar' will print a warning
saying what date it will use. This is to help user ensure he is
using the right date.
13:06:29.152478
...
-`--owner=USER'
- Specifies that `tar' should use USER as the owner of members when
+ When used with '--clamp-mtime' GNU 'tar' will only set the
+ modification date to DATE on files whose actual modification date
+ is later than DATE. This is to make it easy to build reproducible
+ archives given a common timestamp for generated files while still
+ retaining the original timestamps of untouched files.
+
+ $ tar -c -f archive.tar --clamp-mtime --mtime=@$SOURCE_DATE_EPOCH .
+
+'--owner=USER'
+
+ Specifies that 'tar' should use USER as the owner of members when
creating archives, instead of the user associated with the source
file.
If USER contains a colon, it is taken to be of the form NAME:ID
where a nonempty NAME specifies the user name and a nonempty ID
specifies the decimal numeric user ID. If USER does not contain a
- colon, it is taken to be a user number if it is one or more
- decimal digits; otherwise it is taken to be a user name.
+ colon, it is taken to be a user number if it is one or more decimal
+ digits; otherwise it is taken to be a user name.
If a name is given but no number, the number is inferred from the
current host's user database if possible, and the file's user
database is not consulted, and the name and number need not be
valid on the current host.
- There is no value indicating a missing number, and `0' usually
- means `root'. Some people like to force `0' as the value to offer
- in their distributions for the owner of files, because the `root'
+ There is no value indicating a missing number, and '0' usually
+ means 'root'. Some people like to force '0' as the value to offer
+ in their distributions for the owner of files, because the 'root'
user is anonymous anyway, so that might as well be the owner of
anonymous archives. For example:
$ tar -c -f archive.tar --owner=root .
-`--group=GROUP'
- Files added to the `tar' archive will have a group ID of GROUP,
- rather than the group from the source file. As with `--owner',
- the argument GROUP can be an existing group symbolic name, or a
- decimal numeric group ID, or NAME:ID.
+'--group=GROUP'
+
+ Files added to the 'tar' archive will have a group ID of GROUP,
+ rather than the group from the source file. As with '--owner', the
+ argument GROUP can be an existing group symbolic name, or a decimal
+ numeric group ID, or NAME:ID.
+
+ The '--owner' and '--group' options affect all files added to the
+archive. GNU 'tar' provides also two options that allow for more
+detailed control over owner translation:
+
+'--owner-map=FILE'
+ Read UID translation map from FILE.
+
+ When reading, empty lines are ignored. The '#' sign, unless
+ quoted, introduces a comment, which extends to the end of the line.
+ Each nonempty line defines mapping for a single UID. It must
+ consist of two fields separated by any amount of whitespace. The
+ first field defines original username and UID. It can be a valid
+ user name or a valid UID prefixed with a plus sign. In both cases
+ the corresponding UID or user name is inferred from the current
+ host's user database.
+
+ The second field defines the UID and username to map the original
+ one to. Its format can be the same as described above. Otherwise,
+ it can have the form NEWNAME:NEWUID, in which case neither NEWNAME
+ nor NEWUID are required to be valid as per the user database.
+
+ For example, consider the following file:
+
+ +10 bin
+ smith root:0
+
+ Given this file, each input file that is owner by UID 10 will be
+ stored in archive with owner name 'bin' and owner UID corresponding
+ to 'bin'. Each file owned by user 'smith' will be stored with
+ owner name 'root' and owner ID 0. Other files will remain
+ unchanged.
+
+ When used together with '--owner-map', the '--owner' option affects
+ only files whose owner is not listed in the map file.
+
+'--group-map=FILE'
+ Read GID translation map from FILE.
+
+ The format of FILE is the same as for '--owner-map' option:
+
+ Each nonempty line defines mapping for a single GID. It must
+ consist of two fields separated by any amount of whitespace. The
+ first field defines original group name and GID. It can be a valid
+ group name or a valid GID prefixed with a plus sign. In both cases
+ the corresponding GID or user name is inferred from the current
+ host's group database.
+
+ The second field defines the GID and group name to map the original
+ one to. Its format can be the same as described above. Otherwise,
+ it can have the form NEWNAME:NEWGID, in which case neither NEWNAME
+ nor NEWGID are required to be valid as per the group database.
+
+ When used together with '--group-map', the '--group' option affects
+ only files whose owner group is not rewritten using the map file.
+
+\1f
+File: tar.info, Node: Extended File Attributes, Next: Ignore Failed Read, Prev: override, Up: create options
+
+4.3.2 Extended File Attributes
+------------------------------
+
+Extended file attributes are name-value pairs that can be associated
+with each node in a file system. Despite the fact that POSIX.1e draft
+which proposed them has been withdrawn, the extended file attributes are
+supported by many file systems. GNU 'tar' can store extended file
+attributes along with the files. This feature is controlled by the
+following command line arguments:
+
+'--xattrs'
+ Enable extended attributes support. When used with '--create',
+ this option instructs GNU 'tar' to store extended file attribute in
+ the created archive. This implies POSIX.1-2001 archive format
+ ('--format=pax').
+
+ When used with '--extract', this option tells 'tar', for each file
+ extracted, to read stored attributes from the archive and to apply
+ them to the file.
+
+'--no-xattrs'
+ Disable extended attributes support. This is the default.
+
+ Attribute names are strings prefixed by a "namespace" name and a dot.
+Currently, four namespaces exist: 'user', 'trusted', 'security' and
+'system'. By default, when '--xattr' is used, all names are stored in
+the archive (or extracted, if using '--extract'). This can be
+controlled using the following options:
+
+'--xattrs-exclude=PATTERN'
+ Specify exclude pattern for extended attributes.
+
+'--xattrs-include=PATTERN'
+ Specify include pattern for extended attributes.
+
+ Here, the PATTERN is POSIX regular expression. For example, the
+following command:
+
+ $ tar --xattrs --xattrs-exclude='^user\.' -c a.tar .
+
+ will include in the archive 'a.tar' all attributes, except those from
+the 'user' namespace.
+
+ Any number of these options can be given, thereby creating lists of
+include and exclude patterns.
+
+ When both options are used, first '--xattrs-inlcude' is applied to
+select the set of attribute names to keep, and then '--xattrs-exclude'
+is applied to the resulting set. In other words, only those attributes
+will be stored, whose names match one of the regexps in
+'--xattrs-inlcude' and don't match any of the regexps from
+'--xattrs-exclude'.
+
+ When listing the archive, if both '--xattrs' and '--verbose' options
+are given, files that have extended attributes are marked with an
+asterisk following their permission mask. For example:
+
+ -rw-r--r--* smith/users 110 2016-03-16 16:07 file
+
+ When two or more '--verbose' options are given, a detailed listing of
+extended attributes is printed after each file entry. Each attribute is
+listed on a separate line, which begins with two spaces and the letter
+'x' indicating extended attribute. It is followed by a colon, length of
+the attribute and its name, e.g.:
+
+ -rw-r--r--* smith/users 110 2016-03-16 16:07 file
+ x: 7 user.mime_type
+ x: 32 trusted.md5sum
+
+ File access control lists ("ACL") are another actively used feature
+proposed by the POSIX.1e standard. Each ACL consists of a set of ACL
+entries, each of which describes the access permissions on the file for
+an individual user or a group of users as a combination of read, write
+and search/execute permissions.
+
+ Whether or not to use ACLs is controlled by the following two
+options:
+
+'--acls'
+ Enable POSIX ACLs support. When used with '--create', this option
+ instructs GNU 'tar' to store ACLs in the created archive. This
+ implies POSIX.1-2001 archive format ('--format=pax').
+
+ When used with '--extract', this option tells 'tar', to restore
+ ACLs for each file extracted (provided they are present in the
+ archive).
+
+'--no-acls'
+ Disable POSIX ACLs support. This is the default.
+
+ When listing the archive, if both '--acls' and '--verbose' options
+are given, files that have ACLs are marked with a plus sing following
+their permission mask. For example:
+
+ -rw-r--r--+ smith/users 110 2016-03-16 16:07 file
+
+ When two or more '--verbose' options are given, a detailed listing of
+ACL is printed after each file entry:
+
+ -rw-r--r--+ smith/users 110 2016-03-16 16:07 file
+ a: user::rw-,user:gray:-w-,group::r--,mask::rw-,other::r--
+
+ "Security-Enhanced Linux" ("SELinux" for short) is a Linux kernel
+security module that provides a mechanism for supporting access control
+security policies, including so-called mandatory access controls
+("MAC"). Support for SELinux attributes is controlled by the following
+command line options:
+
+'--selinux'
+ Enable the SELinux context support.
+
+'--no-selinux'
+ Disable SELinux context support.
\1f
-File: tar.info, Node: Ignore Failed Read, Prev: override, Up: create options
+File: tar.info, Node: Ignore Failed Read, Prev: Extended File Attributes, Up: create options
-4.3.2 Ignore Fail Read
+4.3.3 Ignore Fail Read
----------------------
-`--ignore-failed-read'
+'--ignore-failed-read'
Do not exit with nonzero on unreadable files or directories.
\1f
File: tar.info, Node: extract options, Next: backup, Prev: create options, Up: operations
-4.4 Options Used by `--extract'
+4.4 Options Used by '--extract'
===============================
-The previous chapter showed how to use `--extract' to extract an
-archive into the file system. Various options cause `tar' to extract
-more information than just file contents, such as the owner, the
-permissions, the modification date, and so forth. This section
-presents options to be used with `--extract' when certain special
-considerations arise. You may review the information presented in
-*note extract:: for more basic information about the `--extract'
-operation.
+The previous chapter showed how to use '--extract' to extract an archive
+into the file system. Various options cause 'tar' to extract more
+information than just file contents, such as the owner, the permissions,
+the modification date, and so forth. This section presents options to
+be used with '--extract' when certain special considerations arise. You
+may review the information presented in *note extract:: for more basic
+information about the '--extract' operation.
* Menu:
* Reading:: Options to Help Read Archives
-* Writing:: Changing How `tar' Writes Files
+* Writing:: Changing How 'tar' Writes Files
* Scarce:: Coping with Scarce Resources
\1f
4.4.1 Options to Help Read Archives
-----------------------------------
-Normally, `tar' will request data in full record increments from an
+Normally, 'tar' will request data in full record increments from an
archive storage device. If the device cannot return a full record,
-`tar' will report an error. However, some devices do not always return
+'tar' will report an error. However, some devices do not always return
full records, or do not require the last record of an archive to be
padded out to the next record boundary. To keep reading until you
obtain a full record, or to accept an incomplete record if it contains
-an end-of-archive marker, specify the `--read-full-records' (`-B')
-option in conjunction with the `--extract' or `--list' operations.
+an end-of-archive marker, specify the '--read-full-records' ('-B')
+option in conjunction with the '--extract' or '--list' operations.
*Note Blocking::.
- The `--read-full-records' (`-B') option is turned on by default when
-`tar' reads an archive from standard input, or from a remote machine.
+ The '--read-full-records' ('-B') option is turned on by default when
+'tar' reads an archive from standard input, or from a remote machine.
This is because on BSD Unix systems, attempting to read a pipe returns
however much happens to be in the pipe, even if it is less than was
-requested. If this option were not enabled, `tar' would fail as soon
-as it read an incomplete record from the pipe.
+requested. If this option were not enabled, 'tar' would fail as soon as
+it read an incomplete record from the pipe.
- If you're not sure of the blocking factor of an archive, you can
-read the archive by specifying `--read-full-records' (`-B') and
-`--blocking-factor=512-SIZE' (`-b 512-SIZE'), using a blocking factor
+ If you're not sure of the blocking factor of an archive, you can read
+the archive by specifying '--read-full-records' ('-B') and
+'--blocking-factor=512-SIZE' ('-b 512-SIZE'), using a blocking factor
larger than what the archive uses. This lets you avoid having to
determine the blocking factor of an archive. *Note Blocking Factor::.
Reading Full Records
....................
-`--read-full-records'
-
-`-B'
- Use in conjunction with `--extract' (`--get', `-x') to read an
+'--read-full-records'
+'-B'
+ Use in conjunction with '--extract' ('--get', '-x') to read an
archive which contains incomplete records, or one which has a
blocking factor less than the one specified.
Ignoring Blocks of Zeros
........................
-Normally, `tar' stops reading when it encounters a block of zeros
+Normally, 'tar' stops reading when it encounters a block of zeros
between file entries (which usually indicates the end of the archive).
-`--ignore-zeros' (`-i') allows `tar' to completely read an archive
-which contains a block of zeros before the end (i.e., a damaged
-archive, or one that was created by concatenating several archives
-together).
-
- The `--ignore-zeros' (`-i') option is turned off by default because
-many versions of `tar' write garbage after the end-of-archive entry,
-since that part of the media is never supposed to be read. GNU `tar'
+'--ignore-zeros' ('-i') allows 'tar' to completely read an archive which
+contains a block of zeros before the end (i.e., a damaged archive, or
+one that was created by concatenating several archives together).
+
+ The '--ignore-zeros' ('-i') option is turned off by default because
+many versions of 'tar' write garbage after the end-of-archive entry,
+since that part of the media is never supposed to be read. GNU 'tar'
does not write after the end of an archive, but seeks to maintain
compatibility among archiving utilities.
-`--ignore-zeros'
-`-i'
+'--ignore-zeros'
+'-i'
To ignore blocks of zeros (i.e., end-of-archive entries) which may
be encountered while reading an archive. Use in conjunction with
- `--extract' or `--list'.
+ '--extract' or '--list'.
\1f
File: tar.info, Node: Writing, Next: Scarce, Prev: Reading, Up: extract options
-4.4.2 Changing How `tar' Writes Files
+4.4.2 Changing How 'tar' Writes Files
-------------------------------------
_(This message will disappear, once this node revised.)_
Options Controlling the Overwriting of Existing Files
.....................................................
-When extracting files, if `tar' discovers that the extracted file
+When extracting files, if 'tar' discovers that the extracted file
already exists, it normally replaces the file by removing it before
extracting it, to prevent confusion in the presence of hard or symbolic
links. (If the existing file is a symbolic link, it is removed, not
followed.) However, if a directory cannot be removed because it is
-nonempty, `tar' normally overwrites its metadata (ownership,
-permission, etc.). The `--overwrite-dir' option enables this default
-behavior. To be more cautious and preserve the metadata of such a
-directory, use the `--no-overwrite-dir' option.
+nonempty, 'tar' normally overwrites its metadata (ownership, permission,
+etc.). The '--overwrite-dir' option enables this default behavior. To
+be more cautious and preserve the metadata of such a directory, use the
+'--no-overwrite-dir' option.
To be even more cautious and prevent existing files from being
-replaced, use the `--keep-old-files' (`-k') option. It causes `tar' to
+replaced, use the '--keep-old-files' ('-k') option. It causes 'tar' to
refuse to replace or update a file that already exists, i.e., a file
with the same name as an archive member prevents extraction of that
archive member. Instead, it reports an error. For example:
tar: blues: Cannot open: File exists
tar: Exiting with failure status due to previous errors
- If you wish to preserve old files untouched, but don't want `tar' to
-treat them as errors, use the `--skip-old-files' option. This option
-causes `tar' to silently skip extracting over existing files.
+ If you wish to preserve old files untouched, but don't want 'tar' to
+treat them as errors, use the '--skip-old-files' option. This option
+causes 'tar' to silently skip extracting over existing files.
To be more aggressive about altering existing files, use the
-`--overwrite' option. It causes `tar' to overwrite existing files and
+'--overwrite' option. It causes 'tar' to overwrite existing files and
to follow existing symbolic links when extracting.
- Some people argue that GNU `tar' should not hesitate to overwrite
-files with other files when extracting. When extracting a `tar'
+ Some people argue that GNU 'tar' should not hesitate to overwrite
+files with other files when extracting. When extracting a 'tar'
archive, they expect to see a faithful copy of the state of the file
system when the archive was created. It is debatable that this would
-always be a proper behavior. For example, suppose one has an archive
-in which `usr/local' is a link to `usr/local2'. Since then, maybe the
-site removed the link and renamed the whole hierarchy from
-`/usr/local2' to `/usr/local'. Such things happen all the time. I
-guess it would not be welcome at all that GNU `tar' removes the whole
-hierarchy just to make room for the link to be reinstated (unless it
-_also_ simultaneously restores the full `/usr/local2', of course!) GNU
-`tar' is indeed able to remove a whole hierarchy to reestablish a
-symbolic link, for example, but _only if_ `--recursive-unlink' is
-specified to allow this behavior. In any case, single files are
-silently removed.
-
- Finally, the `--unlink-first' (`-U') option can improve performance
-in some cases by causing `tar' to remove files unconditionally before
+always be a proper behavior. For example, suppose one has an archive in
+which 'usr/local' is a link to 'usr/local2'. Since then, maybe the site
+removed the link and renamed the whole hierarchy from '/usr/local2' to
+'/usr/local'. Such things happen all the time. I guess it would not be
+welcome at all that GNU 'tar' removes the whole hierarchy just to make
+room for the link to be reinstated (unless it _also_ simultaneously
+restores the full '/usr/local2', of course!) GNU 'tar' is indeed able
+to remove a whole hierarchy to reestablish a symbolic link, for example,
+but _only if_ '--recursive-unlink' is specified to allow this behavior.
+In any case, single files are silently removed.
+
+ Finally, the '--unlink-first' ('-U') option can improve performance
+in some cases by causing 'tar' to remove files unconditionally before
extracting them.
\1f
Overwrite Old Files
...................
-`--overwrite'
+'--overwrite'
Overwrite existing files and directory metadata when extracting
files from an archive.
- This causes `tar' to write extracted files into the file system
- without regard to the files already on the system; i.e., files
- with the same names as archive members are overwritten when the
- archive is extracted. It also causes `tar' to extract the
- ownership, permissions, and time stamps onto any preexisting files
- or directories. If the name of a corresponding file name is a
+ This causes 'tar' to write extracted files into the file system
+ without regard to the files already on the system; i.e., files with
+ the same names as archive members are overwritten when the archive
+ is extracted. It also causes 'tar' to extract the ownership,
+ permissions, and time stamps onto any preexisting files or
+ directories. If the name of a corresponding file name is a
symbolic link, the file pointed to by the symbolic link will be
overwritten instead of the symbolic link itself (if this is
possible). Moreover, special devices, empty directories and even
symbolic links are automatically removed if they are in the way of
extraction.
- Be careful when using the `--overwrite' option, particularly when
- combined with the `--absolute-names' (`-P') option, as this
+ Be careful when using the '--overwrite' option, particularly when
+ combined with the '--absolute-names' ('-P') option, as this
combination can change the contents, ownership or permissions of
any file on your system. Also, many systems do not take kindly to
overwriting files that are currently being executed.
-`--overwrite-dir'
+'--overwrite-dir'
Overwrite the metadata of directories when extracting files from an
archive, but remove other files before extracting.
Keep Old Files
..............
-GNU `tar' provides two options to control its actions in a situation
+GNU 'tar' provides two options to control its actions in a situation
when it is about to extract a file which already exists on disk.
-`--keep-old-files'
-`-k'
+'--keep-old-files'
+'-k'
Do not replace existing files from archive. When such a file is
- encountered, `tar' issues an error message. Upon end of
- extraction, `tar' exits with code 2 (*note exit status::).
+ encountered, 'tar' issues an error message. Upon end of
+ extraction, 'tar' exits with code 2 (*note exit status::).
-`--skip-old-files'
+'--skip-old-files'
Do not replace existing files from archive, but do not treat that
- as error. Such files are silently skipped and do not affect `tar'
+ as error. Such files are silently skipped and do not affect 'tar'
exit status.
Additional verbosity can be obtained using
- `--warning=existing-file' together with that option (*note
+ '--warning=existing-file' together with that option (*note
warnings::).
\1f
Keep Newer Files
................
-`--keep-newer-files'
+'--keep-newer-files'
Do not replace existing files that are newer than their archive
- copies. This option is meaningless with `--list' (`-t').
+ copies. This option is meaningless with '--list' ('-t').
\1f
File: tar.info, Node: Unlink First, Next: Recursive Unlink, Prev: Keep Newer Files, Up: Writing
Unlink First
............
-`--unlink-first'
-`-U'
- Remove files before extracting over them. This can make `tar' run
+'--unlink-first'
+'-U'
+ Remove files before extracting over them. This can make 'tar' run
a bit faster if you know in advance that the extracted files all
- need to be removed. Normally this option slows `tar' down
+ need to be removed. Normally this option slows 'tar' down
slightly, so it is disabled by default.
\1f
Recursive Unlink
................
-`--recursive-unlink'
+'--recursive-unlink'
When this option is specified, try removing files and directory
hierarchies before extracting over them. _This is a dangerous
option!_
- If you specify the `--recursive-unlink' option, `tar' removes
+ If you specify the '--recursive-unlink' option, 'tar' removes
_anything_ that keeps you from extracting a file as far as current
permissions will allow it. This could include removal of the contents
of a full directory hierarchy.
Setting Data Modification Times
...............................
-Normally, `tar' sets the data modification times of extracted files to
+Normally, 'tar' sets the data modification times of extracted files to
the corresponding times recorded for the files in the archive, but
-limits the permissions of extracted files by the current `umask'
+limits the permissions of extracted files by the current 'umask'
setting.
To set the data modification times of extracted files to the time
-when the files were extracted, use the `--touch' (`-m') option in
-conjunction with `--extract' (`--get', `-x').
+when the files were extracted, use the '--touch' ('-m') option in
+conjunction with '--extract' ('--get', '-x').
-`--touch'
-`-m'
- Sets the data modification time of extracted archive members to
- the time they were extracted, not the time recorded for them in
- the archive. Use in conjunction with `--extract' (`--get', `-x').
+'--touch'
+'-m'
+ Sets the data modification time of extracted archive members to the
+ time they were extracted, not the time recorded for them in the
+ archive. Use in conjunction with '--extract' ('--get', '-x').
\1f
File: tar.info, Node: Setting Access Permissions, Next: Directory Modification Times and Permissions, Prev: Data Modification Times, Up: Writing
..........................
To set the modes (access permissions) of extracted files to those
-recorded for those files in the archive, use `--same-permissions' in
-conjunction with the `--extract' (`--get', `-x') operation.
+recorded for those files in the archive, use '--same-permissions' in
+conjunction with the '--extract' ('--get', '-x') operation.
-`--preserve-permissions'
-`--same-permissions'
-`-p'
+'--preserve-permissions'
+'--same-permissions'
+'-p'
Set modes of extracted archive members to those recorded in the
archive, instead of current umask settings. Use in conjunction
- with `--extract' (`--get', `-x').
+ with '--extract' ('--get', '-x').
\1f
File: tar.info, Node: Directory Modification Times and Permissions, Next: Writing to Standard Output, Prev: Setting Access Permissions, Up: Writing
Directory Modification Times and Permissions
............................................
-After successfully extracting a file member, GNU `tar' normally
-restores its permissions and modification times, as described in the
-previous sections. This cannot be done for directories, because after
-extracting a directory `tar' will almost certainly extract files into
-that directory and this will cause the directory modification time to
-be updated. Moreover, restoring that directory permissions may not
-permit file creation within it. Thus, restoring directory permissions
-and modification times must be delayed at least until all files have
-been extracted into that directory. GNU `tar' restores directories
-using the following approach.
+After successfully extracting a file member, GNU 'tar' normally restores
+its permissions and modification times, as described in the previous
+sections. This cannot be done for directories, because after extracting
+a directory 'tar' will almost certainly extract files into that
+directory and this will cause the directory modification time to be
+updated. Moreover, restoring that directory permissions may not permit
+file creation within it. Thus, restoring directory permissions and
+modification times must be delayed at least until all files have been
+extracted into that directory. GNU 'tar' restores directories using the
+following approach.
The extracted directories are created with the mode specified in the
archive, as modified by the umask of the user, which gives sufficient
permissions to allow file creation. The meta-information about the
directory is recorded in the temporary list of directories. When
-preparing to extract next archive member, GNU `tar' checks if the
+preparing to extract next archive member, GNU 'tar' checks if the
directory prefix of this file contains the remembered directory. If it
does not, the program assumes that all files have been extracted into
that directory, restores its modification time and permissions and
removes its entry from the internal list. This approach allows to
correctly restore directory meta-information in the majority of cases,
while keeping memory requirements sufficiently small. It is based on
-the fact, that most `tar' archives use the predefined order of members:
+the fact, that most 'tar' archives use the predefined order of members:
first the directory, then all the files and subdirectories in that
directory.
incremental archives (*note Incremental Dumps::). The member order in
an incremental archive is reversed: first all directory members are
stored, followed by other (non-directory) members. So, when extracting
-from incremental archives, GNU `tar' alters the above procedure. It
+from incremental archives, GNU 'tar' alters the above procedure. It
remembers all restored directories, and restores their meta-data only
after the entire archive has been processed. Notice, that you do not
-need to specify any special options for that, as GNU `tar'
-automatically detects archives in incremental format.
+need to specify any special options for that, as GNU 'tar' automatically
+detects archives in incremental format.
There may be cases, when such processing is required for normal
archives too. Consider the following example:
bar/file
foo/file2
- During the normal operation, after encountering `bar' GNU `tar' will
-assume that all files from the directory `foo' were already extracted
+ During the normal operation, after encountering 'bar' GNU 'tar' will
+assume that all files from the directory 'foo' were already extracted
and will therefore restore its timestamp and permission bits. However,
-after extracting `foo/file2' the directory timestamp will be offset
+after extracting 'foo/file2' the directory timestamp will be offset
again.
To correctly restore directory meta-information in such cases, use
-the `--delay-directory-restore' command line option:
+the '--delay-directory-restore' command line option:
-`--delay-directory-restore'
+'--delay-directory-restore'
Delays restoring of the modification times and permissions of
extracted directories until the end of extraction. This way,
correct meta-information is restored even if the archive has
unusual member ordering.
-`--no-delay-directory-restore'
- Cancel the effect of the previous `--delay-directory-restore'.
- Use this option if you have used `--delay-directory-restore' in
- `TAR_OPTIONS' variable (*note TAR_OPTIONS::) and wish to
+'--no-delay-directory-restore'
+ Cancel the effect of the previous '--delay-directory-restore'. Use
+ this option if you have used '--delay-directory-restore' in
+ 'TAR_OPTIONS' variable (*note TAR_OPTIONS::) and wish to
temporarily disable it.
\1f
Writing to Standard Output
..........................
-To write the extracted files to the standard output, instead of
-creating the files on the file system, use `--to-stdout' (`-O') in
-conjunction with `--extract' (`--get', `-x'). This option is useful if
-you are extracting files to send them through a pipe, and do not need to
-preserve them in the file system. If you extract multiple members,
-they appear on standard output concatenated, in the order they are
-found in the archive.
+To write the extracted files to the standard output, instead of creating
+the files on the file system, use '--to-stdout' ('-O') in conjunction
+with '--extract' ('--get', '-x'). This option is useful if you are
+extracting files to send them through a pipe, and do not need to
+preserve them in the file system. If you extract multiple members, they
+appear on standard output concatenated, in the order they are found in
+the archive.
-`--to-stdout'
-`-O'
+'--to-stdout'
+'-O'
Writes files to the standard output. Use only in conjunction with
- `--extract' (`--get', `-x'). When this option is used, instead of
- creating the files specified, `tar' writes the contents of the
+ '--extract' ('--get', '-x'). When this option is used, instead of
+ creating the files specified, 'tar' writes the contents of the
files extracted to its standard output. This may be useful if you
- are only extracting the files in order to send them through a
- pipe. This option is meaningless with `--list' (`-t').
+ are only extracting the files in order to send them through a pipe.
+ This option is meaningless with '--list' ('-t').
This can be useful, for example, if you have a tar archive containing
a big file and don't want to store the file on disk before processing
tar -xOzf foo.tgz bigfile1 bigfile2 | process
- However, `--to-command' may be more convenient for use with multiple
-files. See the next section.
+ However, '--to-command' may be more convenient for use with multiple
+files. See the next section.
\1f
File: tar.info, Node: Writing to an External Program, Next: remove files, Prev: Writing to Standard Output, Up: Writing
Writing to an External Program
..............................
-You can instruct `tar' to send the contents of each extracted file to
+You can instruct 'tar' to send the contents of each extracted file to
the standard input of an external program:
-`--to-command=COMMAND'
+'--to-command=COMMAND'
Extract files and pipe their contents to the standard input of
COMMAND. When this option is used, instead of creating the files
- specified, `tar' invokes COMMAND and pipes the contents of the
- files to its standard output. The COMMAND may contain command
- line arguments (see *note Running External Commands: external, for
- more detail).
+ specified, 'tar' invokes COMMAND and pipes the contents of the
+ files to its standard output. The COMMAND may contain command line
+ arguments (see *note Running External Commands: external, for more
+ detail).
Notice, that COMMAND is executed once for each regular file
- extracted. Non-regular files (directories, etc.) are ignored when
+ extracted. Non-regular files (directories, etc.) are ignored when
this option is used.
The command can obtain the information about the file it processes
from the following environment variables:
-`TAR_FILETYPE'
- Type of the file. It is a single letter with the following meaning:
+'TAR_FILETYPE'
+ Type of the file. It is a single letter with the following
+ meaning:
f Regular file
d Directory
Currently only regular files are supported.
-`TAR_MODE'
+'TAR_MODE'
File mode, an octal number.
-`TAR_FILENAME'
+'TAR_FILENAME'
The name of the file.
-`TAR_REALNAME'
+'TAR_REALNAME'
Name of the file as stored in the archive.
-`TAR_UNAME'
+'TAR_UNAME'
Name of the file owner.
-`TAR_GNAME'
+'TAR_GNAME'
Name of the file owner group.
-`TAR_ATIME'
- Time of last access. It is a decimal number, representing seconds
+'TAR_ATIME'
+ Time of last access. It is a decimal number, representing seconds
since the Epoch. If the archive provides times with nanosecond
precision, the nanoseconds are appended to the timestamp after a
decimal point.
-`TAR_MTIME'
+'TAR_MTIME'
Time of last modification.
-`TAR_CTIME'
+'TAR_CTIME'
Time of last status change.
-`TAR_SIZE'
+'TAR_SIZE'
Size of the file.
-`TAR_UID'
+'TAR_UID'
UID of the file owner.
-`TAR_GID'
+'TAR_GID'
GID of the file owner.
Additionally, the following variables contain information about tar
mode and the archive being processed:
-`TAR_VERSION'
- GNU `tar' version number.
+'TAR_VERSION'
+ GNU 'tar' version number.
-`TAR_ARCHIVE'
- The name of the archive `tar' is processing.
+'TAR_ARCHIVE'
+ The name of the archive 'tar' is processing.
-`TAR_BLOCKING_FACTOR'
+'TAR_BLOCKING_FACTOR'
Current blocking factor (*note Blocking::).
-`TAR_VOLUME'
- Ordinal number of the volume `tar' is processing.
+'TAR_VOLUME'
+ Ordinal number of the volume 'tar' is processing.
-`TAR_FORMAT'
- Format of the archive being processed. *Note Formats::, for a
+'TAR_FORMAT'
+ Format of the archive being processed. *Note Formats::, for a
complete list of archive format names.
These variables are defined prior to executing the command, so you
--to-command='proc $TAR_FILENAME $TAR_SIZE'
Notice single quotes to prevent variable names from being expanded by
-the shell when invoking `tar'.
+the shell when invoking 'tar'.
- If COMMAND exits with a non-0 status, `tar' will print an error
+ If COMMAND exits with a non-0 status, 'tar' will print an error
message similar to the following:
tar: 2345: Child returned status 1
- Here, `2345' is the PID of the finished process.
+ Here, '2345' is the PID of the finished process.
- If this behavior is not wanted, use `--ignore-command-error':
+ If this behavior is not wanted, use '--ignore-command-error':
-`--ignore-command-error'
+'--ignore-command-error'
Ignore exit codes of subprocesses. Notice that if the program
exits on signal or otherwise terminates abnormally, the error
message will be printed even if this option is used.
-`--no-ignore-command-error'
- Cancel the effect of any previous `--ignore-command-error' option.
- This option is useful if you have set `--ignore-command-error' in
- `TAR_OPTIONS' (*note TAR_OPTIONS::) and wish to temporarily cancel
+'--no-ignore-command-error'
+ Cancel the effect of any previous '--ignore-command-error' option.
+ This option is useful if you have set '--ignore-command-error' in
+ 'TAR_OPTIONS' (*note TAR_OPTIONS::) and wish to temporarily cancel
it.
\1f
Removing Files
..............
-`--remove-files'
+'--remove-files'
Remove files after adding them to the archive.
\1f
Starting File
.............
-`--starting-file=NAME'
-`-K NAME'
+'--starting-file=NAME'
+'-K NAME'
Starts an operation in the middle of an archive. Use in
- conjunction with `--extract' (`--get', `-x') or `--list' (`-t').
+ conjunction with '--extract' ('--get', '-x') or '--list' ('-t').
If a previous attempt to extract files failed due to lack of disk
-space, you can use `--starting-file=NAME' (`-K NAME') to start
+space, you can use '--starting-file=NAME' ('-K NAME') to start
extracting only after member NAME of the archive. This assumes, of
course, that there is now free space, or that you are now extracting
-into a different file system. (You could also choose to suspend `tar',
+into a different file system. (You could also choose to suspend 'tar',
remove unnecessary files from the file system, and then resume the same
-`tar' operation. In this case, `--starting-file' is not necessary.)
+'tar' operation. In this case, '--starting-file' is not necessary.)
See also *note interactive::, and *note exclude::.
\1f
Same Order
..........
-`--same-order'
-`--preserve-order'
-`-s'
- To process large lists of file names on machines with small
- amounts of memory. Use in conjunction with `--compare' (`--diff',
- `-d'), `--list' (`-t') or `--extract' (`--get', `-x').
-
- The `--same-order' (`--preserve-order', `-s') option tells `tar'
-that the list of file names to be listed or extracted is sorted in the
-same order as the files in the archive. This allows a large list of
-names to be used, even on a small machine that would not otherwise be
-able to hold all the names in memory at the same time. Such a sorted
-list can easily be created by running `tar -t' on the archive and
-editing its output.
+'--same-order'
+'--preserve-order'
+'-s'
+ To process large lists of file names on machines with small amounts
+ of memory. Use in conjunction with '--compare' ('--diff', '-d'),
+ '--list' ('-t') or '--extract' ('--get', '-x').
+
+ The '--same-order' ('--preserve-order', '-s') option tells 'tar' that
+the list of file names to be listed or extracted is sorted in the same
+order as the files in the archive. This allows a large list of names to
+be used, even on a small machine that would not otherwise be able to
+hold all the names in memory at the same time. Such a sorted list can
+easily be created by running 'tar -t' on the archive and editing its
+output.
This option is probably never needed on modern computer systems.
4.5 Backup options
==================
-GNU `tar' offers options for making backups of files before writing new
-versions. These options control the details of these backups. They
-may apply to the archive itself before it is created or rewritten, as
-well as individual extracted members. Other GNU programs (`cp',
-`install', `ln', and `mv', for example) offer similar options.
+GNU 'tar' offers options for making backups of files before writing new
+versions. These options control the details of these backups. They may
+apply to the archive itself before it is created or rewritten, as well
+as individual extracted members. Other GNU programs ('cp', 'install',
+'ln', and 'mv', for example) offer similar options.
Backup options may prove unexpectedly useful when extracting archives
containing many members having identical name, or when extracting
please do not learn to depend blindly on the details of the backup
features. For example, currently, directories themselves are never
renamed through using these options, so, extracting a file over a
-directory still has good chances to fail. Also, backup options apply
-to created archives, not only to extracted members. For created
-archives, backups will not be attempted when the archive is a block or
-character device, or when it refers to a remote file.
+directory still has good chances to fail. Also, backup options apply to
+created archives, not only to extracted members. For created archives,
+backups will not be attempted when the archive is a block or character
+device, or when it refers to a remote file.
For the sake of simplicity and efficiency, backups are made by
renaming old files prior to creation or extraction, and not by copying.
occurs after a partial extraction of a file, both the backup and the
partially extracted file are kept.
-`--backup[=METHOD]'
- Back up files that are about to be overwritten or removed.
- Without this option, the original versions are destroyed.
+'--backup[=METHOD]'
+ Back up files that are about to be overwritten or removed. Without
+ this option, the original versions are destroyed.
- Use METHOD to determine the type of backups made. If METHOD is
- not specified, use the value of the `VERSION_CONTROL' environment
- variable. And if `VERSION_CONTROL' is not set, use the `existing'
+ Use METHOD to determine the type of backups made. If METHOD is not
+ specified, use the value of the 'VERSION_CONTROL' environment
+ variable. And if 'VERSION_CONTROL' is not set, use the 'existing'
method.
- This option corresponds to the Emacs variable `version-control';
+ This option corresponds to the Emacs variable 'version-control';
the same values for METHOD are accepted as in Emacs. This option
also allows more descriptive names. The valid METHODs are:
- `t'
- `numbered'
+ 't'
+ 'numbered'
Always make numbered backups.
- `nil'
- `existing'
+ 'nil'
+ 'existing'
Make numbered backups of files that already have them, simple
backups of the others.
- `never'
- `simple'
+ 'never'
+ 'simple'
Always make simple backups.
-
-`--suffix=SUFFIX'
- Append SUFFIX to each backup file made with `--backup'. If this
- option is not specified, the value of the `SIMPLE_BACKUP_SUFFIX'
- environment variable is used. And if `SIMPLE_BACKUP_SUFFIX' is not
- set, the default is `~', just as in Emacs.
-
+'--suffix=SUFFIX'
+ Append SUFFIX to each backup file made with '--backup'. If this
+ option is not specified, the value of the 'SIMPLE_BACKUP_SUFFIX'
+ environment variable is used. And if 'SIMPLE_BACKUP_SUFFIX' is not
+ set, the default is '~', just as in Emacs.
\1f
File: tar.info, Node: Applications, Next: looking ahead, Prev: backup, Up: operations
-4.6 Notable `tar' Usages
+4.6 Notable 'tar' Usages
========================
_(This message will disappear, once this node revised.)_
-You can easily use archive files to transport a group of files from one
-system to another: put all relevant files into an archive on one
-computer system, transfer the archive to another system, and extract
-the contents there. The basic transfer medium might be magnetic tape,
+ You can easily use archive files to transport a group of files from
+one system to another: put all relevant files into an archive on one
+computer system, transfer the archive to another system, and extract the
+contents there. The basic transfer medium might be magnetic tape,
Internet FTP, or even electronic mail (though you must encode the
-archive with `uuencode' in order to transport it properly by mail).
+archive with 'uuencode' in order to transport it properly by mail).
Both machines do not have to use the same operating system, as long as
-they both support the `tar' program.
+they both support the 'tar' program.
For example, here is how you might copy a directory's contents from
one disk to another, while preserving the dates, modes, owners and
$ (cd sourcedir; tar -cf - .) | (cd targetdir; tar -xf -)
-You can avoid subshells by using `-C' option:
+You can avoid subshells by using '-C' option:
$ tar -C sourcedir -cf - . | tar -C targetdir -xf -
$ tar --directory sourcedir --create --file=- . \
| tar --directory targetdir --extract --file=-
-This is one of the easiest methods to transfer a `tar' archive.
+This is one of the easiest methods to transfer a 'tar' archive.
\1f
File: tar.info, Node: looking ahead, Prev: Applications, Up: operations
==========================================
You have now seen how to use all eight of the operations available to
-`tar', and a number of the possible options. The next chapter explains
+'tar', and a number of the possible options. The next chapter explains
how to choose and change file and archive names, how to use files to
-store names of other files which you can then call as arguments to
-`tar' (this can help you save time if you expect to archive the same
-list of files a number of times), and so forth.
+store names of other files which you can then call as arguments to 'tar'
+(this can help you save time if you expect to archive the same list of
+files a number of times), and so forth.
If there are too many files to conveniently list on the command line,
-you can list the names in a file, and `tar' will read that file. *Note
+you can list the names in a file, and 'tar' will read that file. *Note
files::.
- There are various ways of causing `tar' to skip over some files, and
+ There are various ways of causing 'tar' to skip over some files, and
not archive them. *Note Choosing::.
\1f
5 Performing Backups and Restoring Files
****************************************
-GNU `tar' is distributed along with the scripts for performing backups
+GNU 'tar' is distributed along with the scripts for performing backups
and restores. Even if there is a good chance those scripts may be
satisfying to you, they are not the only scripts or methods available
for doing backups and restore. You may well create your own, or use
more sophisticated packages dedicated to that purpose.
- Some users are enthusiastic about `Amanda' (The Advanced Maryland
+ Some users are enthusiastic about 'Amanda' (The Advanced Maryland
Automatic Network Disk Archiver), a backup system developed by James da
-Silva `jds@cs.umd.edu' and available on many Unix systems. This is
-free software, and it is available from `http://www.amanda.org'.
+Silva 'jds@cs.umd.edu' and available on many Unix systems. This is free
+software, and it is available from <http://www.amanda.org>.
- This chapter documents both the provided shell scripts and `tar'
+ This chapter documents both the provided shell scripts and 'tar'
options which are more specific to usage as a backup tool.
To "back up" a file system means to create archives that contain all
* Menu:
-* Full Dumps:: Using `tar' to Perform Full Dumps
-* Incremental Dumps:: Using `tar' to Perform Incremental Dumps
+* Full Dumps:: Using 'tar' to Perform Full Dumps
+* Incremental Dumps:: Using 'tar' to Perform Incremental Dumps
* Backup Levels:: Levels of Backups
* Backup Parameters:: Setting Parameters for Backups and Restoration
* Scripted Backups:: Using the Backup Scripts
\1f
File: tar.info, Node: Full Dumps, Next: Incremental Dumps, Up: Backups
-5.1 Using `tar' to Perform Full Dumps
+5.1 Using 'tar' to Perform Full Dumps
=====================================
_(This message will disappear, once this node revised.)_
-Full dumps should only be made when no other people or programs are
-modifying files in the file system. If files are modified while `tar'
-is making the backup, they may not be stored properly in the archive,
-in which case you won't be able to restore them if you have to. (Files
-not being modified are written with no trouble, and do not corrupt the
+ Full dumps should only be made when no other people or programs are
+modifying files in the file system. If files are modified while 'tar'
+is making the backup, they may not be stored properly in the archive, in
+which case you won't be able to restore them if you have to. (Files not
+being modified are written with no trouble, and do not corrupt the
entire archive.)
- You will want to use the `--label=ARCHIVE-LABEL' (`-V
-ARCHIVE-LABEL') option to give the archive a volume label, so you can
-tell what this archive is even if the label falls off the tape, or
-anything like that.
+ You will want to use the '--label=ARCHIVE-LABEL' ('-V ARCHIVE-LABEL')
+option to give the archive a volume label, so you can tell what this
+archive is even if the label falls off the tape, or anything like that.
Unless the file system you are dumping is guaranteed to fit on one
-volume, you will need to use the `--multi-volume' (`-M') option. Make
+volume, you will need to use the '--multi-volume' ('-M') option. Make
sure you have enough tapes on hand to complete the backup.
If you want to dump each file system separately you will need to use
-the `--one-file-system' option to prevent `tar' from crossing file
+the '--one-file-system' option to prevent 'tar' from crossing file
system boundaries when storing (sub)directories.
- The `--incremental' (`-G') (*note Incremental Dumps::) option is not
+ The '--incremental' ('-G') (*note Incremental Dumps::) option is not
needed, since this is a complete copy of everything in the file system,
and a full restore from this backup would only be done onto a completely
empty disk.
- Unless you are in a hurry, and trust the `tar' program (and your
-tapes), it is a good idea to use the `--verify' (`-W') option, to make
+ Unless you are in a hurry, and trust the 'tar' program (and your
+tapes), it is a good idea to use the '--verify' ('-W') option, to make
sure your files really made it onto the dump properly. This will also
detect cases where the file was modified while (or just after) it was
being archived. Not all media (notably cartridge tapes) are capable of
\1f
File: tar.info, Node: Incremental Dumps, Next: Backup Levels, Prev: Full Dumps, Up: Backups
-5.2 Using `tar' to Perform Incremental Dumps
+5.2 Using 'tar' to Perform Incremental Dumps
============================================
-"Incremental backup" is a special form of GNU `tar' archive that stores
+"Incremental backup" is a special form of GNU 'tar' archive that stores
additional metadata so that exact state of the file system can be
restored when extracting the archive.
- GNU `tar' currently offers two options for handling incremental
-backups: `--listed-incremental=SNAPSHOT-FILE' (`-g SNAPSHOT-FILE') and
-`--incremental' (`-G').
+ GNU 'tar' currently offers two options for handling incremental
+backups: '--listed-incremental=SNAPSHOT-FILE' ('-g SNAPSHOT-FILE') and
+'--incremental' ('-G').
- The option `--listed-incremental' instructs tar to operate on an
+ The option '--listed-incremental' instructs tar to operate on an
incremental archive with additional metadata stored in a standalone
file, called a "snapshot file". The purpose of this file is to help
-determine which files have been changed, added or deleted since the
-last backup, so that the next incremental backup will contain only
-modified files. The name of the snapshot file is given as an argument
-to the option:
+determine which files have been changed, added or deleted since the last
+backup, so that the next incremental backup will contain only modified
+files. The name of the snapshot file is given as an argument to the
+option:
-`--listed-incremental=FILE'
-`-g FILE'
+'--listed-incremental=FILE'
+'-g FILE'
Handle incremental backups with snapshot data in FILE.
- To create an incremental backup, you would use
-`--listed-incremental' together with `--create' (*note create::). For
-example:
+ To create an incremental backup, you would use '--listed-incremental'
+together with '--create' (*note create::). For example:
$ tar --create \
--file=archive.1.tar \
--listed-incremental=/var/log/usr.snar \
/usr
- This will create in `archive.1.tar' an incremental backup of the
-`/usr' file system, storing additional metadata in the file
-`/var/log/usr.snar'. If this file does not exist, it will be created.
-The created archive will then be a "level 0 backup"; please see the
-next section for more on backup levels.
+ This will create in 'archive.1.tar' an incremental backup of the
+'/usr' file system, storing additional metadata in the file
+'/var/log/usr.snar'. If this file does not exist, it will be created.
+The created archive will then be a "level 0 backup"; please see the next
+section for more on backup levels.
- Otherwise, if the file `/var/log/usr.snar' exists, it determines
+ Otherwise, if the file '/var/log/usr.snar' exists, it determines
which files are modified. In this case only these files will be stored
in the archive. Suppose, for example, that after running the above
-command, you delete file `/usr/doc/old' and create directory
-`/usr/local/db' with the following contents:
+command, you delete file '/usr/doc/old' and create directory
+'/usr/local/db' with the following contents:
$ ls /usr/local/db
/usr/local/db/data
/usr/local/db/index
- Some time later you create another incremental backup. You will
-then see:
+ Some time later you create another incremental backup. You will then
+see:
$ tar --create \
--file=archive.2.tar \
usr/local/db/data
usr/local/db/index
-The created archive `archive.2.tar' will contain only these three
+The created archive 'archive.2.tar' will contain only these three
members. This archive is called a "level 1 backup". Notice that
-`/var/log/usr.snar' will be updated with the new data, so if you plan
-to create more `level 1' backups, it is necessary to create a working
-copy of the snapshot file before running `tar'. The above example will
-then be modified as follows:
+'/var/log/usr.snar' will be updated with the new data, so if you plan to
+create more 'level 1' backups, it is necessary to create a working copy
+of the snapshot file before running 'tar'. The above example will then
+be modified as follows:
$ cp /var/log/usr.snar /var/log/usr.snar-1
$ tar --create \
--listed-incremental=/var/log/usr.snar-1 \
/usr
- You can force `level 0' backups either by removing the snapshot file
-before running `tar', or by supplying the `--level=0' option, e.g.:
+ You can force 'level 0' backups either by removing the snapshot file
+before running 'tar', or by supplying the '--level=0' option, e.g.:
$ tar --create \
--file=archive.2.tar \
/usr
Incremental dumps depend crucially on time stamps, so the results are
-unreliable if you modify a file's time stamps during dumping (e.g.,
-with the `--atime-preserve=replace' option), or if you set the clock
+unreliable if you modify a file's time stamps during dumping (e.g., with
+the '--atime-preserve=replace' option), or if you set the clock
backwards.
Metadata stored in snapshot files include device numbers, which,
-obviously are supposed to be non-volatile values. However, it turns
-out that NFS devices have undependable values when an automounter gets
-in the picture. This can lead to a great deal of spurious redumping in
+obviously are supposed to be non-volatile values. However, it turns out
+that NFS devices have undependable values when an automounter gets in
+the picture. This can lead to a great deal of spurious redumping in
incremental dumps, so it is somewhat useless to compare two NFS devices
numbers over time. The solution implemented currently is to consider
all NFS devices as being equal when it comes to comparing directories;
Apart from using NFS, there are a number of cases where relying on
device numbers can cause spurious redumping of unmodified files. For
example, this occurs when archiving LVM snapshot volumes. To avoid
-this, use `--no-check-device' option:
+this, use '--no-check-device' option:
-`--no-check-device'
+'--no-check-device'
Do not rely on device numbers when preparing a list of changed
files for an incremental dump.
-`--check-device'
+'--check-device'
Use device numbers when preparing a list of changed files for an
incremental dump. This is the default behavior. The purpose of
- this option is to undo the effect of the `--no-check-device' if it
- was given in `TAR_OPTIONS' environment variable (*note
+ this option is to undo the effect of the '--no-check-device' if it
+ was given in 'TAR_OPTIONS' environment variable (*note
TAR_OPTIONS::).
There is also another way to cope with changing device numbers. It
is described in detail in *note Fixing Snapshot Files::.
- Note that incremental archives use `tar' extensions and may not be
-readable by non-GNU versions of the `tar' program.
+ Note that incremental archives use 'tar' extensions and may not be
+readable by non-GNU versions of the 'tar' program.
- To extract from the incremental dumps, use `--listed-incremental'
-together with `--extract' option (*note extracting files::). In this
-case, `tar' does not need to access snapshot file, since all the data
+ To extract from the incremental dumps, use '--listed-incremental'
+together with '--extract' option (*note extracting files::). In this
+case, 'tar' does not need to access snapshot file, since all the data
necessary for extraction are stored in the archive itself. So, when
-extracting, you can give whatever argument to `--listed-incremental',
-the usual practice is to use `--listed-incremental=/dev/null'.
-Alternatively, you can use `--incremental', which needs no arguments.
-In general, `--incremental' (`-G') can be used as a shortcut for
-`--listed-incremental' when listing or extracting incremental backups
+extracting, you can give whatever argument to '--listed-incremental',
+the usual practice is to use '--listed-incremental=/dev/null'.
+Alternatively, you can use '--incremental', which needs no arguments.
+In general, '--incremental' ('-G') can be used as a shortcut for
+'--listed-incremental' when listing or extracting incremental backups
(for more information regarding this option, *note incremental-op::).
- When extracting from the incremental backup GNU `tar' attempts to
+ When extracting from the incremental backup GNU 'tar' attempts to
restore the exact state the file system had when the archive was
-created. In particular, it will _delete_ those files in the file
-system that did not exist in their directories when the archive was
-created. If you have created several levels of incremental files, then
-in order to restore the exact contents the file system had when the
-last level was created, you will need to restore from all backups in
-turn. Continuing our example, to restore the state of `/usr' file
-system, one would do(1):
+created. In particular, it will _delete_ those files in the file system
+that did not exist in their directories when the archive was created.
+If you have created several levels of incremental files, then in order
+to restore the exact contents the file system had when the last level
+was created, you will need to restore from all backups in turn.
+Continuing our example, to restore the state of '/usr' file system, one
+would do(1):
$ tar --extract \
--listed-incremental=/dev/null \
--listed-incremental=/dev/null \
--file archive.2.tar
- To list the contents of an incremental archive, use `--list' (*note
+ To list the contents of an incremental archive, use '--list' (*note
list::), as usual. To obtain more information about the archive, use
-`--listed-incremental' or `--incremental' combined with two `--verbose'
+'--listed-incremental' or '--incremental' combined with two '--verbose'
options(2):
- tar --list --incremental --verbose --verbose archive.tar
+ tar --list --incremental --verbose --verbose --file archive.tar
This command will print, for each directory in the archive, the list
of files in that directory at the time the archive was created. This
X FILE
-where X is a letter describing the status of the file: `Y' if the file
-is present in the archive, `N' if the file is not included in the
-archive, or a `D' if the file is a directory (and is included in the
-archive). *Note Dumpdir::, for the detailed description of dumpdirs
-and status codes. Each such line is terminated by a newline character.
-The last line is followed by an additional newline to indicate the end
-of the data.
-
- The option `--incremental' (`-G') gives the same behavior as
-`--listed-incremental' when used with `--list' and `--extract' options.
-When used with `--create' option, it creates an incremental archive
+where X is a letter describing the status of the file: 'Y' if the file
+is present in the archive, 'N' if the file is not included in the
+archive, or a 'D' if the file is a directory (and is included in the
+archive). *Note Dumpdir::, for the detailed description of dumpdirs and
+status codes. Each such line is terminated by a newline character. The
+last line is followed by an additional newline to indicate the end of
+the data.
+
+ The option '--incremental' ('-G') gives the same behavior as
+'--listed-incremental' when used with '--list' and '--extract' options.
+When used with '--create' option, it creates an incremental archive
without creating snapshot file. Thus, it is impossible to create
-several levels of incremental backups with `--incremental' option.
+several levels of incremental backups with '--incremental' option.
---------- Footnotes ----------
- (1) Notice, that since both archives were created without `-P'
-option (*note absolute::), these commands should be run from the root
-file system.
+ (1) Notice, that since both archives were created without '-P' option
+(*note absolute::), these commands should be run from the root file
+system.
- (2) Two `--verbose' options were selected to avoid breaking usual
-verbose listing output (`--list --verbose') when using in scripts.
+ (2) Two '--verbose' options were selected to avoid breaking usual
+verbose listing output ('--list --verbose') when using in scripts.
- Versions of GNU `tar' up to 1.15.1 used to dump verbatim binary
+ Versions of GNU 'tar' up to 1.15.1 used to dump verbatim binary
contents of the DUMPDIR header (with terminating nulls) when
-`--incremental' or `--listed-incremental' option was given, no matter
+'--incremental' or '--listed-incremental' option was given, no matter
what the verbosity level. This behavior, and, especially, the binary
output it produced were considered inconvenient and were changed in
version 1.16.
5.3 Levels of Backups
=====================
-An archive containing all the files in the file system is called a
-"full backup" or "full dump". You could insure your data by creating a
-full dump every day. This strategy, however, would waste a substantial
+An archive containing all the files in the file system is called a "full
+backup" or "full dump". You could insure your data by creating a full
+dump every day. This strategy, however, would waste a substantial
amount of archive media and user time, as unchanged files are daily
re-archived.
dump.
A typical dump strategy would be to perform a full dump once a week,
-and a level one dump once a day. This means some versions of files
-will in fact be archived more than once, but this dump strategy makes
-it possible to restore a file system to within one day of accuracy by
-only extracting two archives--the last weekly (full) dump and the last
-daily (level one) dump. The only information lost would be in files
-changed or created since the last daily backup. (Doing dumps more than
-once a day is usually not worth the trouble.)
-
- GNU `tar' comes with scripts you can use to do full and level-one
+and a level one dump once a day. This means some versions of files will
+in fact be archived more than once, but this dump strategy makes it
+possible to restore a file system to within one day of accuracy by only
+extracting two archives--the last weekly (full) dump and the last daily
+(level one) dump. The only information lost would be in files changed
+or created since the last daily backup. (Doing dumps more than once a
+day is usually not worth the trouble.)
+
+ GNU 'tar' comes with scripts you can use to do full and level-one
(actually, even level-two and so on) dumps. Using scripts (shell
programs) to perform backups and restoration is a convenient and
-reliable alternative to typing out file name lists and `tar' commands
-by hand.
+reliable alternative to typing out file name lists and 'tar' commands by
+hand.
Before you use these scripts, you need to edit the file
-`backup-specs', which specifies parameters used by the backup scripts
+'backup-specs', which specifies parameters used by the backup scripts
and by the restore script. This file is usually located in
-`/etc/backup' directory. *Note Backup Parameters::, for its detailed
+'/etc/backup' directory. *Note Backup Parameters::, for its detailed
description. Once the backup parameters are set, you can perform
backups or restoration by running the appropriate script.
- The name of the backup script is `backup'. The name of the restore
-script is `restore'. The following sections describe their use in
+ The name of the backup script is 'backup'. The name of the restore
+script is 'restore'. The following sections describe their use in
detail.
_Please Note:_ The backup and restoration scripts are designed to be
5.4 Setting Parameters for Backups and Restoration
==================================================
-The file `backup-specs' specifies backup parameters for the backup and
-restoration scripts provided with `tar'. You must edit `backup-specs'
+The file 'backup-specs' specifies backup parameters for the backup and
+restoration scripts provided with 'tar'. You must edit 'backup-specs'
to fit your system configuration and schedule before using these
scripts.
- Syntactically, `backup-specs' is a shell script, containing mainly
+ Syntactically, 'backup-specs' is a shell script, containing mainly
variable assignments. However, any valid shell construct is allowed in
this file. Particularly, you may wish to define functions within that
-script (e.g., see `RESTORE_BEGIN' below). For more information about
-shell script syntax, please refer to the definition of the Shell
-Command Language
+script (e.g., see 'RESTORE_BEGIN' below). For more information about
+shell script syntax, please refer to the definition of the Shell Command
+Language
(http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#ta
g_02). See also *note Bash Features: (bashref)Top.
- The shell variables controlling behavior of `backup' and `restore'
+ The shell variables controlling behavior of 'backup' and 'restore'
are described in the following subsections.
* Menu:
* General-Purpose Variables::
* Magnetic Tape Control::
* User Hooks::
-* backup-specs example:: An Example Text of `Backup-specs'
+* backup-specs example:: An Example Text of 'Backup-specs'
\1f
File: tar.info, Node: General-Purpose Variables, Next: Magnetic Tape Control, Up: Backup Parameters
-------------------------------
-- Backup variable: ADMINISTRATOR
- The user name of the backup administrator. `Backup' scripts sends
+ The user name of the backup administrator. 'Backup' scripts sends
a backup report to this address.
-- Backup variable: BACKUP_HOUR
The hour at which the backups are done. This can be a number from
0 to 23, or the time specification in form HOURS:MINUTES, or the
- string `now'.
+ string 'now'.
- This variable is used by `backup'. Its value may be overridden
- using `--time' option (*note Scripted Backups::).
+ This variable is used by 'backup'. Its value may be overridden
+ using '--time' option (*note Scripted Backups::).
-- Backup variable: TAPE_FILE
- The device `tar' writes the archive to. If TAPE_FILE is a remote
+
+ The device 'tar' writes the archive to. If TAPE_FILE is a remote
archive (*note remote-dev::), backup script will suppose that your
- `mt' is able to access remote devices. If RSH (*note RSH::) is
- set, `--rsh-command' option will be added to invocations of `mt'.
+ 'mt' is able to access remote devices. If RSH (*note RSH::) is
+ set, '--rsh-command' option will be added to invocations of 'mt'.
-- Backup variable: BLOCKING
- The blocking factor `tar' will use when writing the dump archive.
+
+ The blocking factor 'tar' will use when writing the dump archive.
*Note Blocking Factor::.
-- Backup variable: BACKUP_DIRS
- A list of file systems to be dumped (for `backup'), or restored
- (for `restore'). You can include any directory name in the list
- -- subdirectories on that file system will be included, regardless
- of how they may look to other networked machines. Subdirectories
- on other file systems will be ignored.
- The host name specifies which host to run `tar' on, and should
+ A list of file systems to be dumped (for 'backup'), or restored
+ (for 'restore'). You can include any directory name in the list --
+ subdirectories on that file system will be included, regardless of
+ how they may look to other networked machines. Subdirectories on
+ other file systems will be ignored.
+
+ The host name specifies which host to run 'tar' on, and should
normally be the host that actually contains the file system.
- However, the host machine must have GNU `tar' installed, and must
+ However, the host machine must have GNU 'tar' installed, and must
be able to access the directory containing the backup scripts and
their support files using the same file name that is used on the
- machine where the scripts are run (i.e., what `pwd' will print
- when in that directory on that machine). If the host that contains
- the file system does not have this capability, you can specify
- another host as long as it can access the file system through NFS.
+ machine where the scripts are run (i.e., what 'pwd' will print when
+ in that directory on that machine). If the host that contains the
+ file system does not have this capability, you can specify another
+ host as long as it can access the file system through NFS.
If the list of file systems is very long you may wish to put it in
- a separate file. This file is usually named `/etc/backup/dirs',
- but this name may be overridden in `backup-specs' using `DIRLIST'
+ a separate file. This file is usually named '/etc/backup/dirs',
+ but this name may be overridden in 'backup-specs' using 'DIRLIST'
variable.
-- Backup variable: DIRLIST
+
The name of the file that contains a list of file systems to backup
- or restore. By default it is `/etc/backup/dirs'.
+ or restore. By default it is '/etc/backup/dirs'.
-- Backup variable: BACKUP_FILES
- A list of individual files to be dumped (for `backup'), or restored
- (for `restore'). These should be accessible from the machine on
+
+ A list of individual files to be dumped (for 'backup'), or restored
+ (for 'restore'). These should be accessible from the machine on
which the backup script is run.
If the list of individual files is very long you may wish to store
it in a separate file. This file is usually named
- `/etc/backup/files', but this name may be overridden in
- `backup-specs' using `FILELIST' variable.
+ '/etc/backup/files', but this name may be overridden in
+ 'backup-specs' using 'FILELIST' variable.
-- Backup variable: FILELIST
+
The name of the file that contains a list of individual files to
- backup or restore. By default it is `/etc/backup/files'.
+ backup or restore. By default it is '/etc/backup/files'.
-- Backup variable: MT
- Full file name of `mt' binary.
+
+ Full file name of 'mt' binary.
-- Backup variable: RSH
- Full file name of `rsh' binary or its equivalent. You may wish to
- set it to `ssh', to improve security. In this case you will have
+ Full file name of 'rsh' binary or its equivalent. You may wish to
+ set it to 'ssh', to improve security. In this case you will have
to use public key authentication.
-- Backup variable: RSH_COMMAND
- Full file name of `rsh' binary on remote machines. This will be
- passed via `--rsh-command' option to the remote invocation of GNU
- `tar'.
+
+ Full file name of 'rsh' binary on remote machines. This will be
+ passed via '--rsh-command' option to the remote invocation of GNU
+ 'tar'.
-- Backup variable: VOLNO_FILE
+
Name of temporary file to hold volume numbers. This needs to be
accessible by all the machines which have file systems to be
dumped.
-- Backup variable: XLIST
+
Name of "exclude file list". An "exclude file list" is a file
located on the remote machine and containing the list of files to
be excluded from the backup. Exclude file lists are searched in
/etc/tar-backup directory. A common use for exclude file lists is
to exclude files containing security-sensitive information (e.g.,
- `/etc/shadow' from backups).
+ '/etc/shadow' from backups).
- This variable affects only `backup'.
+ This variable affects only 'backup'.
-- Backup variable: SLEEP_TIME
+
Time to sleep between dumps of any two successive file systems
- This variable affects only `backup'.
+ This variable affects only 'backup'.
-- Backup variable: DUMP_REMIND_SCRIPT
+
Script to be run when it's time to insert a new tape in for the
next volume. Administrators may want to tailor this script for
- their site. If this variable isn't set, GNU `tar' will display
- its built-in prompt, and will expect confirmation from the
- console. For the description of the default prompt, see *note
- change volume prompt::.
-
+ their site. If this variable isn't set, GNU 'tar' will display its
+ built-in prompt, and will expect confirmation from the console.
+ For the description of the default prompt, see *note change volume
+ prompt::.
-- Backup variable: SLEEP_MESSAGE
+
Message to display on the terminal while waiting for dump time.
Usually this will just be some literal text.
-- Backup variable: TAR
- Full file name of the GNU `tar' executable. If this is not set,
- backup scripts will search `tar' in the current shell path.
+
+ Full file name of the GNU 'tar' executable. If this is not set,
+ backup scripts will search 'tar' in the current shell path.
\1f
File: tar.info, Node: Magnetic Tape Control, Next: User Hooks, Prev: General-Purpose Variables, Up: Backup Parameters
5.4.2 Magnetic Tape Control
---------------------------
-Backup scripts access tape device using special "hook functions".
-These functions take a single argument -- the name of the tape device.
-Their names are kept in the following variables:
+Backup scripts access tape device using special "hook functions". These
+functions take a single argument -- the name of the tape device. Their
+names are kept in the following variables:
-- Backup variable: MT_BEGIN
The name of "begin" function. This function is called before
mt -f "$1" rewind
}
-
-- Backup variable: MT_OFFLINE
The name of the function switching the tape off line. By default
it is defined as follows:
5.4.3 User Hooks
----------------
-"User hooks" are shell functions executed before and after each `tar'
+"User hooks" are shell functions executed before and after each 'tar'
invocation. Thus, there are "backup hooks", which are executed before
-and after dumping each file system, and "restore hooks", executed
-before and after restoring a file system. Each user hook is a shell
-function taking four arguments:
+and after dumping each file system, and "restore hooks", executed before
+and after restoring a file system. Each user hook is a shell function
+taking four arguments:
-- User Hook Function: hook LEVEL HOST FS FSNAME
Its arguments are:
- LEVEL
+ LEVEL
Current backup or restore level.
- HOST
+ HOST
Name or IP address of the host machine being dumped or
restored.
- FS
+ FS
Full file name of the file system being dumped or restored.
- FSNAME
+ FSNAME
File system name with directory separators replaced with
colons. This is useful, e.g., for creating unique files.
\1f
File: tar.info, Node: backup-specs example, Prev: User Hooks, Up: Backup Parameters
-5.4.4 An Example Text of `Backup-specs'
+5.4.4 An Example Text of 'Backup-specs'
---------------------------------------
-The following is an example of `backup-specs':
+The following is an example of 'backup-specs':
# site-specific parameters for file system backup.
BACKUP_HOUR=1
TAPE_FILE=/dev/nrsmt0
- # Use `ssh' instead of the less secure `rsh'
+ # Use ssh instead of the less secure rsh
RSH=/usr/bin/ssh
RSH_COMMAND=/usr/bin/ssh
BACKUP_FILES="/com/mailer/aliases /com/mailer/league*[a-z]"
+
\1f
File: tar.info, Node: Scripted Backups, Next: Scripted Restoration, Prev: Backup Parameters, Up: Backups
backup --level=LEVEL --time=TIME
- The `--level' option requests the dump level. Thus, to produce a
-full dump, specify `--level=0' (this is the default, so `--level' may
-be omitted if its value is `0')(1).
+ The '--level' option requests the dump level. Thus, to produce a
+full dump, specify '--level=0' (this is the default, so '--level' may be
+omitted if its value is '0')(1).
- The `--time' option determines when should the backup be run. TIME
+ The '--time' option determines when should the backup be run. TIME
may take three forms:
HH:MM
+
The dump must be run at HH hours MM minutes.
HH
+
The dump must be run at HH hours.
now
+
The dump must be run immediately.
You should start a script with a tape or disk mounted. Once you
start a script, it prompts you for new tapes or disks as it needs them.
Media volumes don't have to correspond to archive files -- a
-multi-volume archive can be started in the middle of a tape that
-already contains the end of another multi-volume archive. The
-`restore' script prompts for media by its archive volume, so to avoid
-an error message you should keep track of which tape (or disk) contains
-which volume of the archive (*note Scripted Restoration::).
+multi-volume archive can be started in the middle of a tape that already
+contains the end of another multi-volume archive. The 'restore' script
+prompts for media by its archive volume, so to avoid an error message
+you should keep track of which tape (or disk) contains which volume of
+the archive (*note Scripted Restoration::).
The backup scripts write two files on the file system. The first is
-a record file in `/etc/tar-backup/', which is used by the scripts to
-store and retrieve information about which files were dumped. This
-file is not meant to be read by humans, and should not be deleted by
-them. *Note Snapshot Files::, for a more detailed explanation of this
-file.
+a record file in '/etc/tar-backup/', which is used by the scripts to
+store and retrieve information about which files were dumped. This file
+is not meant to be read by humans, and should not be deleted by them.
+*Note Snapshot Files::, for a more detailed explanation of this file.
The second file is a log file containing the names of the file
systems and files dumped, what time the backup was made, and any error
messages that were generated, as well as how much space was left in the
media volume after the last volume of the archive was written. You
should check this log file after every backup. The file name is
-`log-MM-DD-YYYY-level-N', where MM-DD-YYYY represents current date, and
+'log-MM-DD-YYYY-level-N', where MM-DD-YYYY represents current date, and
N represents current dump level number.
The script also prints the name of each system being dumped to the
standard output.
- Following is the full list of options accepted by `backup' script:
+ Following is the full list of options accepted by 'backup' script:
-`-l LEVEL'
-`--level=LEVEL'
+'-l LEVEL'
+'--level=LEVEL'
Do backup level LEVEL (default 0).
-`-f'
-`--force'
+'-f'
+'--force'
Force backup even if today's log file already exists.
-`-v[LEVEL]'
-`--verbose[=LEVEL]'
+'-v[LEVEL]'
+'--verbose[=LEVEL]'
Set verbosity level. The higher the level is, the more debugging
- information will be output during execution. Default LEVEL is
- 100, which means the highest debugging level.
+ information will be output during execution. Default LEVEL is 100,
+ which means the highest debugging level.
-`-t START-TIME'
-`--time=START-TIME'
+'-t START-TIME'
+'--time=START-TIME'
Wait till TIME, then do backup.
-`-h'
-`--help'
+'-h'
+'--help'
Display short help message and exit.
-`-V'
-`--version'
+'-V'
+'--version'
Display information about the program's name, version, origin and
legal status, all on standard output, and then exit successfully.
---------- Footnotes ----------
- (1) For backward compatibility, the `backup' will also try to deduce
+ (1) For backward compatibility, the 'backup' will also try to deduce
the requested dump level from the name of the script itself. If the
-name consists of a string `level-' followed by a single decimal digit,
+name consists of a string 'level-' followed by a single decimal digit,
that digit is taken as the dump level number. Thus, you may create a
-link from `backup' to `level-1' and then run `level-1' whenever you
-need to create a level one dump.
+link from 'backup' to 'level-1' and then run 'level-1' whenever you need
+to create a level one dump.
\1f
File: tar.info, Node: Scripted Restoration, Prev: Scripted Backups, Up: Backups
============================
To restore files that were archived using a scripted backup, use the
-`restore' script. Its usage is quite straightforward. In the simplest
-form, invoke `restore --all', it will then restore all the file systems
-and files specified in `backup-specs' (*note BACKUP_DIRS:
+'restore' script. Its usage is quite straightforward. In the simplest
+form, invoke 'restore --all', it will then restore all the file systems
+and files specified in 'backup-specs' (*note BACKUP_DIRS:
General-Purpose Variables.).
You may select the file systems (and/or files) to restore by giving
-`restore' a list of "patterns" in its command line. For example,
+'restore' a list of "patterns" in its command line. For example,
running
restore 'albert:*'
-will restore all file systems on the machine `albert'. A more
+will restore all file systems on the machine 'albert'. A more
complicated example:
restore 'albert:*' '*:/var'
-This command will restore all file systems on the machine `albert' as
-well as `/var' file system on all machines.
+This command will restore all file systems on the machine 'albert' as
+well as '/var' file system on all machines.
- By default `restore' will start restoring files from the lowest
+ By default 'restore' will start restoring files from the lowest
available dump level (usually zero) and will continue through all
available dump levels. There may be situations where such a thorough
restore is not necessary. For example, you may wish to restore only
-files from the recent level one backup. To do so, use `--level'
-option, as shown in the example below:
+files from the recent level one backup. To do so, use '--level' option,
+as shown in the example below:
restore --level=1
- The full list of options accepted by `restore' follows:
+ The full list of options accepted by 'restore' follows:
-`-a'
-`--all'
- Restore all file systems and files specified in `backup-specs'.
+'-a'
+'--all'
+ Restore all file systems and files specified in 'backup-specs'.
-`-l LEVEL'
-`--level=LEVEL'
- Start restoring from the given backup level, instead of the
- default 0.
+'-l LEVEL'
+'--level=LEVEL'
+ Start restoring from the given backup level, instead of the default
+ 0.
-`-v[LEVEL]'
-`--verbose[=LEVEL]'
+'-v[LEVEL]'
+'--verbose[=LEVEL]'
Set verbosity level. The higher the level is, the more debugging
- information will be output during execution. Default LEVEL is
- 100, which means the highest debugging level.
+ information will be output during execution. Default LEVEL is 100,
+ which means the highest debugging level.
-`-h'
-`--help'
+'-h'
+'--help'
Display short help message and exit.
-`-V'
-`--version'
+'-V'
+'--version'
Display information about the program's name, version, origin and
legal status, all on standard output, and then exit successfully.
past the beginning of the archive, the script will rewind the tape as
needed. *Note Tape Positioning::, for a discussion of tape positioning.
- *Warning:* The script will delete files from the active file
- system if they were not in the file system when the archive was
- made.
+ *Warning:* The script will delete files from the active file system
+ if they were not in the file system when the archive was made.
*Note Incremental Dumps::, for an explanation of how the script makes
that determination.
\1f
File: tar.info, Node: Choosing, Next: Date input formats, Prev: Backups, Up: Top
-6 Choosing Files and Names for `tar'
+6 Choosing Files and Names for 'tar'
************************************
-Certain options to `tar' enable you to specify a name for your archive.
+Certain options to 'tar' enable you to specify a name for your archive.
Other options let you decide which files to include or exclude from the
archive, based on when or whether files were modified, whether the file
names do or don't match specified patterns, or whether files are in
6.1 Choosing and Naming Archive Files
=====================================
-By default, `tar' uses an archive file name that was compiled when it
+By default, 'tar' uses an archive file name that was compiled when it
was built on the system; usually this name refers to some physical tape
-drive on the machine. However, the person who installed `tar' on the
-system may not have set the default to a meaningful value as far as
-most users are concerned. As a result, you will usually want to tell
-`tar' where to find (or create) the archive. The `--file=ARCHIVE-NAME'
-(`-f ARCHIVE-NAME') option allows you to either specify or name a file
-to use as the archive instead of the default archive file location.
-
-`--file=ARCHIVE-NAME'
-`-f ARCHIVE-NAME'
+drive on the machine. However, the person who installed 'tar' on the
+system may not have set the default to a meaningful value as far as most
+users are concerned. As a result, you will usually want to tell 'tar'
+where to find (or create) the archive. The '--file=ARCHIVE-NAME' ('-f
+ARCHIVE-NAME') option allows you to either specify or name a file to use
+as the archive instead of the default archive file location.
+
+'--file=ARCHIVE-NAME'
+'-f ARCHIVE-NAME'
Name the archive to create or operate on. Use in conjunction with
any operation.
- For example, in this `tar' command,
+ For example, in this 'tar' command,
$ tar -cvf collection.tar blues folk jazz
-`collection.tar' is the name of the archive. It must directly follow
-the `-f' option, since whatever directly follows `-f' _will_ end up
+'collection.tar' is the name of the archive. It must directly follow
+the '-f' option, since whatever directly follows '-f' _will_ end up
naming the archive. If you neglect to specify an archive name, you may
end up overwriting a file in the working directory with the archive you
-create since `tar' will use this file's name for the archive name.
+create since 'tar' will use this file's name for the archive name.
An archive can be saved as a file in the file system, sent through a
pipe or over a network, or written to an I/O device such as a tape,
floppy disk, or CD write drive.
- If you do not name the archive, `tar' uses the value of the
-environment variable `TAPE' as the file name for the archive. If that
-is not available, `tar' uses a default, compiled-in archive name,
-usually that for tape unit zero (i.e., `/dev/tu00').
+ If you do not name the archive, 'tar' uses the value of the
+environment variable 'TAPE' as the file name for the archive. If that
+is not available, 'tar' uses a default, compiled-in archive name,
+usually that for tape unit zero (i.e., '/dev/tu00').
- If you use `-' as an ARCHIVE-NAME, `tar' reads the archive from
+ If you use '-' as an ARCHIVE-NAME, 'tar' reads the archive from
standard input (when listing or extracting files), or writes it to
-standard output (when creating an archive). If you use `-' as an
-ARCHIVE-NAME when modifying an archive, `tar' reads the original
-archive from its standard input and writes the entire new archive to
-its standard output.
+standard output (when creating an archive). If you use '-' as an
+ARCHIVE-NAME when modifying an archive, 'tar' reads the original archive
+from its standard input and writes the entire new archive to its
+standard output.
The following example is a convenient way of copying directory
-hierarchy from `sourcedir' to `targetdir'.
+hierarchy from 'sourcedir' to 'targetdir'.
$ (cd sourcedir; tar -cf - .) | (cd targetdir; tar -xpf -)
- The `-C' option allows to avoid using subshells:
+ The '-C' option allows to avoid using subshells:
$ tar -C sourcedir -cf - . | tar -C targetdir -xpf -
- In both examples above, the leftmost `tar' invocation archives the
-contents of `sourcedir' to the standard output, while the rightmost one
-reads this archive from its standard input and extracts it. The `-p'
+ In both examples above, the leftmost 'tar' invocation archives the
+contents of 'sourcedir' to the standard output, while the rightmost one
+reads this archive from its standard input and extracts it. The '-p'
option tells it to restore permissions of the extracted files.
To specify an archive file on a device attached to a remote machine,
--file=HOSTNAME:/DEV/FILE-NAME
-`tar' will set up the remote connection, if possible, and prompt you
-for a username and password. If you use
-`--file=@HOSTNAME:/DEV/FILE-NAME', `tar' will attempt to set up the
-remote connection using your username as the username on the remote
-machine.
+'tar' will set up the remote connection, if possible, and prompt you for
+a username and password. If you use '--file=@HOSTNAME:/DEV/FILE-NAME',
+'tar' will attempt to set up the remote connection using your username
+as the username on the remote machine.
- If the archive file name includes a colon (`:'), then it is assumed
+ If the archive file name includes a colon (':'), then it is assumed
to be a file on another machine. If the archive file is
-`USER@HOST:FILE', then FILE is used on the host HOST. The remote host
-is accessed using the `rsh' program, with a username of USER. If the
-username is omitted (along with the `@' sign), then your user name will
-be used. (This is the normal `rsh' behavior.) It is necessary for the
-remote machine, in addition to permitting your `rsh' access, to have
-the `rmt' program installed (this command is included in the GNU `tar'
-distribution and by default is installed under `PREFIX/libexec/rmt',
-where PREFIX means your installation prefix). If you need to use a
-file whose name includes a colon, then the remote tape drive behavior
-can be inhibited by using the `--force-local' option.
-
- When the archive is being created to `/dev/null', GNU `tar' tries to
+'USER@HOST:FILE', then FILE is used on the host HOST. The remote host
+is accessed using the 'rsh' program, with a username of USER. If the
+username is omitted (along with the '@' sign), then your user name will
+be used. (This is the normal 'rsh' behavior.) It is necessary for the
+remote machine, in addition to permitting your 'rsh' access, to have the
+'rmt' program installed (this command is included in the GNU 'tar'
+distribution and by default is installed under 'PREFIX/libexec/rmt',
+where PREFIX means your installation prefix). If you need to use a file
+whose name includes a colon, then the remote tape drive behavior can be
+inhibited by using the '--force-local' option.
+
+ When the archive is being created to '/dev/null', GNU 'tar' tries to
minimize input and output operations. The Amanda backup system, when
-used with GNU `tar', has an initial sizing pass which uses this feature.
+used with GNU 'tar', has an initial sizing pass which uses this feature.
\1f
File: tar.info, Node: Selecting Archive Members, Next: files, Prev: file, Up: Choosing
6.2 Selecting Archive Members
=============================
-"File Name arguments" specify which files in the file system `tar'
+"File Name arguments" specify which files in the file system 'tar'
operates on, when creating or adding to an archive, or which archive
-members `tar' operates on, when reading or deleting from an archive.
+members 'tar' operates on, when reading or deleting from an archive.
*Note Operations::.
To specify file names, you can include them as the last arguments on
the command line, as follows:
tar OPERATION [OPTION1 OPTION2 ...] [FILE NAME-1 FILE NAME-2 ...]
- If a file name begins with dash (`-'), precede it with `--add-file'
+ If a file name begins with dash ('-'), precede it with '--add-file'
option to prevent it from being treated as an option.
- By default GNU `tar' attempts to "unquote" each file or member name,
+ By default GNU 'tar' attempts to "unquote" each file or member name,
replacing "escape sequences" according to the following table:
Escape Replaced with
------------------------------------------------------------
+-----------------------------------------------------------
\a Audible bell (ASCII 7)
\b Backspace (ASCII 8)
\f Form feed (ASCII 12)
\t Horizontal tabulation (ASCII 9)
\v Vertical tabulation (ASCII 11)
\? ASCII 127
-\N ASCII N (N should be an octal number
- of up to 3 digits)
+\N ASCII N (N should be an octal number of
+ up to 3 digits)
A backslash followed by any other symbol is retained.
This default behavior is controlled by the following command line
option:
-`--unquote'
+'--unquote'
Enable unquoting input file or member names (default).
-`--no-unquote'
+'--no-unquote'
Disable unquoting input file or member names.
If you specify a directory name as a file name argument, all the
-files in that directory are operated on by `tar'.
+files in that directory are operated on by 'tar'.
- If you do not specify files, `tar' behavior differs depending on the
+ If you do not specify files, 'tar' behavior differs depending on the
operation mode as described below:
- When `tar' is invoked with `--create' (`-c'), `tar' will stop
+ When 'tar' is invoked with '--create' ('-c'), 'tar' will stop
immediately, reporting the following:
$ tar cf a.tar
tar: Cowardly refusing to create an empty archive
Try 'tar --help' or 'tar --usage' for more information.
- If you specify either `--list' (`-t') or `--extract' (`--get',
-`-x'), `tar' operates on all the archive members in the archive.
+ If you specify either '--list' ('-t') or '--extract' ('--get', '-x'),
+'tar' operates on all the archive members in the archive.
- If run with `--diff' option, tar will compare the archive with the
+ If run with '--diff' option, tar will compare the archive with the
contents of the current working directory.
- If you specify any other operation, `tar' does nothing.
+ If you specify any other operation, 'tar' does nothing.
- By default, `tar' takes file names from the command line. However,
+ By default, 'tar' takes file names from the command line. However,
there are other ways to specify file or member names, or to modify the
-manner in which `tar' selects the files or members upon which to
+manner in which 'tar' selects the files or members upon which to
operate. In general, these methods work both for specifying the names
of files and archive members.
Instead of giving the names of files or archive members on the command
line, you can put the names into a file, and then use the
-`--files-from=FILE-OF-NAMES' (`-T FILE-OF-NAMES') option to `tar'.
-Give the name of the file which contains the list of files to include
-as the argument to `--files-from'. In the list, the file names should
-be separated by newlines. You will frequently use this option when you
-have generated the list of files to archive with the `find' utility.
-
-`--files-from=FILE-NAME'
-`-T FILE-NAME'
+'--files-from=FILE-OF-NAMES' ('-T FILE-OF-NAMES') option to 'tar'. Give
+the name of the file which contains the list of files to include as the
+argument to '--files-from'. In the list, the file names should be
+separated by newlines. You will frequently use this option when you
+have generated the list of files to archive with the 'find' utility.
+
+'--files-from=FILE-NAME'
+'-T FILE-NAME'
Get names to extract or create from file FILE-NAME.
- If you give a single dash as a file name for `--files-from', (i.e.,
-you specify either `--files-from=-' or `-T -'), then the file names are
+ If you give a single dash as a file name for '--files-from', (i.e.,
+you specify either '--files-from=-' or '-T -'), then the file names are
read from standard input.
- Unless you are running `tar' with `--create', you can not use both
-`--files-from=-' and `--file=-' (`-f -') in the same command.
+ Unless you are running 'tar' with '--create', you cannot use both
+'--files-from=-' and '--file=-' ('-f -') in the same command.
- Any number of `-T' options can be given in the command line.
+ Any number of '-T' options can be given in the command line.
- The following example shows how to use `find' to generate a list of
+ The following example shows how to use 'find' to generate a list of
files smaller than 400K in length and put that list into a file called
-`small-files'. You can then use the `-T' option to `tar' to specify
-the files from that file, `small-files', to create the archive
-`little.tgz'. (The `-z' option to `tar' compresses the archive with
-`gzip'; *note gzip:: for more information.)
+'small-files'. You can then use the '-T' option to 'tar' to specify the
+files from that file, 'small-files', to create the archive 'little.tgz'.
+(The '-z' option to 'tar' compresses the archive with 'gzip'; *note
+gzip:: for more information.)
$ find . -size -400 -print > small-files
$ tar -c -v -z -T small-files -f little.tgz
-In the file list given by `-T' option, any file name beginning with `-'
-character is considered a `tar' option and is processed accordingly(1).
-For example, the common use of this feature is to change to another
-directory by specifying `-C' option:
+By default, each line read from the file list is first stripped off any
+leading and trailing whitespace. If the resulting string begins with
+'-' character, it is considered a 'tar' option and is processed
+accordingly(1). For example, the common use of this feature is to
+change to another directory by specifying '-C' option:
$ cat list
-C/etc
libc.a
$ tar -c -f foo.tar --files-from list
-In this example, `tar' will first switch to `/etc' directory and add
-files `passwd' and `hosts' to the archive. Then it will change to
-`/lib' directory and will archive the file `libc.a'. Thus, the
-resulting archive `foo.tar' will contain:
+In this example, 'tar' will first switch to '/etc' directory and add
+files 'passwd' and 'hosts' to the archive. Then it will change to
+'/lib' directory and will archive the file 'libc.a'. Thus, the
+resulting archive 'foo.tar' will contain:
$ tar tf foo.tar
passwd
hosts
libc.a
- If you happen to have a file whose name starts with `-', precede it
-with `--add-file' option to prevent it from being recognized as an
-option. For example: `--add-file=--my-file'.
+ Note, that any options used in the file list remain in effect for the
+rest of the command line. For example, using the same 'list' file as
+above, the following command
+
+ $ tar -c -f foo.tar --files-from list libcurses.a
+
+will look for file 'libcurses.a' in the directory '/lib', because it was
+used with the last '-C' option (*note Position-Sensitive Options::).
+
+ If such option handling is undesirable, use the
+'--verbatim-files-from' option. When this option is in effect, each
+line read from the file list is treated as a file name. Notice, that
+this means, in particular, that no whitespace trimming is performed.
+
+ The '--verbatim-files-from' affects all '-T' options that follow it
+in the command line. The default behavior can be restored using
+'--no-verbatim-files-from' option.
+
+ To disable option handling for a single file name, use the
+'--add-file' option, e.g.: '--add-file=--my-file'.
+
+ You can use any GNU 'tar' command line options in the file list file,
+including '--files-from' option itself. This allows for including
+contents of a file list into another file list file. Note however, that
+options that control file list processing, such as
+'--verbatim-files-from' or '--null' won't affect the file they appear
+in. They will affect next '--files-from' option, if there is any.
* Menu:
---------- Footnotes ----------
- (1) Versions of GNU `tar' up to 1.15.1 recognized only `-C' option
-in file lists, and only if the option and its argument occupied two
+ (1) Versions of GNU 'tar' up to 1.15.1 recognized only '-C' option in
+file lists, and only if the option and its argument occupied two
consecutive lines.
\1f
File: tar.info, Node: nul, Up: files
-6.3.1 `NUL'-Terminated File Names
+6.3.1 'NUL'-Terminated File Names
---------------------------------
-The `--null' option causes `--files-from=FILE-OF-NAMES' (`-T
-FILE-OF-NAMES') to read file names terminated by a `NUL' instead of a
+The '--null' option causes '--files-from=FILE-OF-NAMES' ('-T
+FILE-OF-NAMES') to read file names terminated by a 'NUL' instead of a
newline, so files whose names contain newlines can be archived using
-`--files-from'.
+'--files-from'.
-`--null'
- Only consider `NUL'-terminated file names, instead of files that
+'--null'
+ Only consider 'NUL'-terminated file names, instead of files that
terminate in a newline.
-`--no-null'
- Undo the effect of any previous `--null' option.
+'--no-null'
+ Undo the effect of any previous '--null' option.
- The `--null' option is just like the one in GNU `xargs' and `cpio',
-and is useful with the `-print0' predicate of GNU `find'. In `tar',
-`--null' also disables special handling for file names that begin with
-dash.
+ The '--null' option is just like the one in GNU 'xargs' and 'cpio',
+and is useful with the '-print0' predicate of GNU 'find'. In 'tar',
+'--null' also disables special handling for file names that begin with
+dash (similar to '--verbatim-files-from' option).
- This example shows how to use `find' to generate a list of files
+ This example shows how to use 'find' to generate a list of files
larger than 800K in length and put that list into a file called
-`long-files'. The `-print0' option to `find' is just like `-print',
-except that it separates files with a `NUL' rather than with a newline.
-You can then run `tar' with both the `--null' and `-T' options to
-specify that `tar' gets the files from that file, `long-files', to
-create the archive `big.tgz'. The `--null' option to `tar' will cause
-`tar' to recognize the `NUL' separator between files.
+'long-files'. The '-print0' option to 'find' is just like '-print',
+except that it separates files with a 'NUL' rather than with a newline.
+You can then run 'tar' with both the '--null' and '-T' options to
+specify that 'tar' gets the files from that file, 'long-files', to
+create the archive 'big.tgz'. The '--null' option to 'tar' will cause
+'tar' to recognize the 'NUL' separator between files.
$ find . -size +800 -print0 > long-files
$ tar -c -v --null --files-from=long-files --file=big.tar
- The `--no-null' option can be used if you need to read both
-`NUL'-terminated and newline-terminated files on the same command line.
-For example, if `flist' is a newline-terminated file, then the
-following command can be used to combine it with the above command:
+ The '--no-null' option can be used if you need to read both
+'NUL'-terminated and newline-terminated files on the same command line.
+For example, if 'flist' is a newline-terminated file, then the following
+command can be used to combine it with the above command:
$ find . -size +800 -print0 |
tar -c -f big.tar --null -T - --no-null -T flist
This example uses short options for typographic reasons, to avoid
very long lines.
- GNU `tar' is tries to automatically detect `NUL'-terminated file
-lists, so in many cases it is safe to use them even without the
-`--null' option. In this case `tar' will print a warning and continue
-reading such a file as if `--null' were actually given:
+ GNU 'tar' is tries to automatically detect 'NUL'-terminated file
+lists, so in many cases it is safe to use them even without the '--null'
+option. In this case 'tar' will print a warning and continue reading
+such a file as if '--null' were actually given:
$ find . -size +800 -print0 | tar -c -f big.tar -T -
tar: -: file name read contains nul character
The null terminator, however, remains in effect only for this
-particular file, any following `-T' options will assume newline
+particular file, any following '-T' options will assume newline
termination. Of course, the null autodetection applies to these
-eventual surplus `-T' options as well.
+eventual surplus '-T' options as well.
\1f
File: tar.info, Node: exclude, Next: wildcards, Prev: files, Up: Choosing
========================
To avoid operating on files whose names match a particular pattern, use
-the `--exclude' or `--exclude-from' options.
+the '--exclude' or '--exclude-from' options.
-`--exclude=PATTERN'
- Causes `tar' to ignore files that match the PATTERN.
+'--exclude=PATTERN'
+ Causes 'tar' to ignore files that match the PATTERN.
- The `--exclude=PATTERN' option prevents any file or member whose
-name matches the shell wildcard (PATTERN) from being operated on. For
+ The '--exclude=PATTERN' option prevents any file or member whose name
+matches the shell wildcard (PATTERN) from being operated on. For
example, to create an archive with all the contents of the directory
-`src' except for files whose names end in `.o', use the command `tar
--cf src.tar --exclude='*.o' src'.
+'src' except for files whose names end in '.o', use the command 'tar -cf
+src.tar --exclude='*.o' src'.
- You may give multiple `--exclude' options.
+ You may give multiple '--exclude' options.
-`--exclude-from=FILE'
-`-X FILE'
- Causes `tar' to ignore files that match the patterns listed in
+'--exclude-from=FILE'
+'-X FILE'
+ Causes 'tar' to ignore files that match the patterns listed in
FILE.
- Use the `--exclude-from' option to read a list of patterns, one per
-line, from FILE; `tar' will ignore files matching those patterns. Thus
-if `tar' is called as `tar -c -X foo .' and the file `foo' contains a
-single line `*.o', no files whose names end in `.o' will be added to
-the archive.
+ Use the '--exclude-from' option to read a list of patterns, one per
+line, from FILE; 'tar' will ignore files matching those patterns. Thus
+if 'tar' is called as 'tar -c -X foo .' and the file 'foo' contains a
+single line '*.o', no files whose names end in '.o' will be added to the
+archive.
- Notice, that lines from FILE are read verbatim. One of the frequent
+ Notice, that lines from FILE are read verbatim. One of the frequent
errors is leaving some extra whitespace after a file name, which is
difficult to catch using text editors.
However, empty lines are OK.
- When archiving directories that are under some version control
-system (VCS), it is often convenient to read exclusion patterns from
-this VCS' ignore files (e.g. `.cvsignore', `.gitignore', etc.) The
-following options provide such possibilty:
+ When archiving directories that are under some version control system
+(VCS), it is often convenient to read exclusion patterns from this VCS'
+ignore files (e.g. '.cvsignore', '.gitignore', etc.) The following
+options provide such possibility:
-`--exclude-vcs-ignores'
+'--exclude-vcs-ignores'
Before archiving a directory, see if it contains any of the
- following files: `cvsignore', `.gitignore', `.bzrignore', or
- `.hgignore'. If so, read ignore patterns from these files.
+ following files: 'cvsignore', '.gitignore', '.bzrignore', or
+ '.hgignore'. If so, read ignore patterns from these files.
The patterns are treated much as the corresponding VCS would treat
them, i.e.:
- `.cvsignore'
+ '.cvsignore'
Contains shell-style globbing patterns that apply only to the
- directory where this file resides. No comments are allowed
- in the file. Empty lines are ignored.
+ directory where this file resides. No comments are allowed in
+ the file. Empty lines are ignored.
- `.gitignore'
+ '.gitignore'
Contains shell-style globbing patterns. Applies to the
- directory where `.gitfile' is located and all its
+ directory where '.gitfile' is located and all its
subdirectories.
- Any line beginning with a `#' is a comment. Backslash escapes
+ Any line beginning with a '#' is a comment. Backslash escapes
the comment character.
- `.bzrignore'
+ '.bzrignore'
Contains shell globbing-patterns and regular expressions (if
- prefixed with `RE:'(1). Patterns affect the directory and
- all its subdirectories.
+ prefixed with 'RE:'(1). Patterns affect the directory and all
+ its subdirectories.
- Any line beginning with a `#' is a comment.
+ Any line beginning with a '#' is a comment.
- `.hgignore'
- Contains posix regular expressions(2). The line `syntax:
- glob' switches to shell globbing patterns. The line `syntax:
- regexp' switches back. Comments begin with a `#'. Patterns
+ '.hgignore'
+ Contains posix regular expressions(2). The line 'syntax:
+ glob' switches to shell globbing patterns. The line 'syntax:
+ regexp' switches back. Comments begin with a '#'. Patterns
affect the directory and all its subdirectories.
-`--exclude-ignore=FILE'
- Before dumping a directory, `tar' checks if it contains FILE. If
+'--exclude-ignore=FILE'
+ Before dumping a directory, 'tar' checks if it contains FILE. If
so, exclusion patterns are read from this file. The patterns
affect only the directory itself.
-`--exclude-ignore-recursive=FILE'
- Same as `--exclude-ignore', except that the patterns read affect
+'--exclude-ignore-recursive=FILE'
+ Same as '--exclude-ignore', except that the patterns read affect
both the directory where FILE resides and all its subdirectories.
-`--exclude-vcs'
+'--exclude-vcs'
Exclude files and directories used by following version control
- systems: `CVS', `RCS', `SCCS', `SVN', `Arch', `Bazaar',
- `Mercurial', and `Darcs'.
-
- As of version 1.28, the following files are excluded:
-
- * `CVS/', and everything under it
-
- * `RCS/', and everything under it
-
- * `SCCS/', and everything under it
-
- * `.git/', and everything under it
-
- * `.gitignore'
-
- * `.cvsignore'
-
- * `.svn/', and everything under it
-
- * `.arch-ids/', and everything under it
-
- * `{arch}/', and everything under it
-
- * `=RELEASE-ID'
-
- * `=meta-update'
-
- * `=update'
-
- * `.bzr'
-
- * `.bzrignore'
-
- * `.bzrtags'
-
- * `.hg'
-
- * `.hgignore'
-
- * `.hgrags'
-
- * `_darcs'
-
-`--exclude-backups'
+ systems: 'CVS', 'RCS', 'SCCS', 'SVN', 'Arch', 'Bazaar',
+ 'Mercurial', and 'Darcs'.
+
+ As of version 1.29, the following files are excluded:
+
+ * 'CVS/', and everything under it
+ * 'RCS/', and everything under it
+ * 'SCCS/', and everything under it
+ * '.git/', and everything under it
+ * '.gitignore'
+ * '.gitmodules'
+ * '.gitattributes'
+ * '.cvsignore'
+ * '.svn/', and everything under it
+ * '.arch-ids/', and everything under it
+ * '{arch}/', and everything under it
+ * '=RELEASE-ID'
+ * '=meta-update'
+ * '=update'
+ * '.bzr'
+ * '.bzrignore'
+ * '.bzrtags'
+ * '.hg'
+ * '.hgignore'
+ * '.hgrags'
+ * '_darcs'
+
+'--exclude-backups'
Exclude backup and lock files. This option causes exclusion of
files that match the following shell globbing patterns:
- .#*
-
- *~
-
- #*#
-
+ .#*
+ *~
+ #*#
- When creating an archive, the `--exclude-caches' option family
-causes `tar' to exclude all directories that contain a "cache directory
-tag". A cache directory tag is a short file with the well-known name
-`CACHEDIR.TAG' and having a standard header specified in
-`http://www.brynosaurus.com/cachedir/spec.html'. Various applications
+ When creating an archive, the '--exclude-caches' option family causes
+'tar' to exclude all directories that contain a "cache directory tag".
+A cache directory tag is a short file with the well-known name
+'CACHEDIR.TAG' and having a standard header specified in
+<http://www.brynosaurus.com/cachedir/spec.html>. Various applications
write cache directory tags into directories they use to hold
regenerable, non-precious data, so that such data can be more easily
excluded from backups.
- There are three `exclude-caches' options, each providing a different
+ There are three 'exclude-caches' options, each providing a different
exclusion semantics:
-`--exclude-caches'
+'--exclude-caches'
Do not archive the contents of the directory, but archive the
- directory itself and the `CACHEDIR.TAG' file.
+ directory itself and the 'CACHEDIR.TAG' file.
-`--exclude-caches-under'
+'--exclude-caches-under'
Do not archive the contents of the directory, nor the
- `CACHEDIR.TAG' file, archive only the directory itself.
+ 'CACHEDIR.TAG' file, archive only the directory itself.
-`--exclude-caches-all'
- Omit directories containing `CACHEDIR.TAG' file entirely.
+'--exclude-caches-all'
+ Omit directories containing 'CACHEDIR.TAG' file entirely.
- Another option family, `--exclude-tag', provides a generalization of
-this concept. It takes a single argument, a file name to look for.
-Any directory that contains this file will be excluded from the dump.
-Similarly to `exclude-caches', there are three options in this option
+ Another option family, '--exclude-tag', provides a generalization of
+this concept. It takes a single argument, a file name to look for. Any
+directory that contains this file will be excluded from the dump.
+Similarly to 'exclude-caches', there are three options in this option
family:
-`--exclude-tag=FILE'
+'--exclude-tag=FILE'
Do not dump the contents of the directory, but dump the directory
itself and the FILE.
-`--exclude-tag-under=FILE'
+'--exclude-tag-under=FILE'
Do not dump the contents of the directory, nor the FILE, archive
only the directory itself.
-`--exclude-tag-all=FILE'
+'--exclude-tag-all=FILE'
Omit directories containing FILE file entirely.
- Multiple `--exclude-tag*' options can be given.
+ Multiple '--exclude-tag*' options can be given.
For example, given this directory:
dir/folk/sanjuan
dir/folk/trote
- The `--exclude-tag' will produce the following:
+ The '--exclude-tag' will produce the following:
$ tar -cf archive.tar --exclude-tag=tagfile -v dir
dir/
contents not dumped
dir/folk/tagfile
- Both the `dir/folk' directory and its tagfile are preserved in the
+ Both the 'dir/folk' directory and its tagfile are preserved in the
archive, however the rest of files in this directory are not.
- Now, using the `--exclude-tag-under' option will exclude `tagfile'
+ Now, using the '--exclude-tag-under' option will exclude 'tagfile'
from the dump, while still preserving the directory itself, as shown in
this example:
./tar: dir/folk/: contains a cache directory tag tagfile;
contents not dumped
- Finally, using `--exclude-tag-all' omits the `dir/folk' directory
+ Finally, using '--exclude-tag-all' omits the 'dir/folk' directory
entirely:
$ tar -cf archive.tar --exclude-tag-all=tagfile -v dir
---------- Footnotes ----------
(1) According to the Bazaar docs, globbing-patterns are Korn-shell
-style and regular expressions are perl-style. As of GNU `tar' version
-1.28, these are treated as shell-style globs and posix extended
-regexps. This will be fixed in future releases.
+style and regular expressions are perl-style. As of GNU 'tar' version
+1.29, these are treated as shell-style globs and posix extended regexps.
+This will be fixed in future releases.
(2) Support for perl-style regexps will appear in future releases.
\1f
File: tar.info, Node: problems with exclude, Up: exclude
-Problems with Using the `exclude' Options
+Problems with Using the 'exclude' Options
-----------------------------------------
-Some users find `exclude' options confusing. Here are some common
+Some users find 'exclude' options confusing. Here are some common
pitfalls:
- * The main operating mode of `tar' does not act on a file name
+ * The main operating mode of 'tar' does not act on a file name
explicitly listed on the command line, if one of its file name
components is excluded. In the example above, if you create an
- archive and exclude files that end with `*.o', but explicitly name
- the file `dir.o/foo' after all the options have been listed,
- `dir.o/foo' will be excluded from the archive.
+ archive and exclude files that end with '*.o', but explicitly name
+ the file 'dir.o/foo' after all the options have been listed,
+ 'dir.o/foo' will be excluded from the archive.
- * You can sometimes confuse the meanings of `--exclude' and
- `--exclude-from'. Be careful: use `--exclude' when files to be
+ * You can sometimes confuse the meanings of '--exclude' and
+ '--exclude-from'. Be careful: use '--exclude' when files to be
excluded are given as a pattern on the command line. Use
- `--exclude-from' to introduce the name of a file which contains a
+ '--exclude-from' to introduce the name of a file which contains a
list of patterns, one per line; each of these patterns can exclude
zero, one, or many files.
- * When you use `--exclude=PATTERN', be sure to quote the PATTERN
- parameter, so GNU `tar' sees wildcard characters like `*'. If you
- do not do this, the shell might expand the `*' itself using files
- at hand, so `tar' might receive a list of files instead of one
- pattern, or none at all, making the command somewhat illegal.
- This might not correspond to what you want.
+ * When you use '--exclude=PATTERN', be sure to quote the PATTERN
+ parameter, so GNU 'tar' sees wildcard characters like '*'. If you
+ do not do this, the shell might expand the '*' itself using files
+ at hand, so 'tar' might receive a list of files instead of one
+ pattern, or none at all, making the command somewhat illegal. This
+ might not correspond to what you want.
For example, write:
# _Wrong!_
$ tar -c -f ARCHIVE.TAR --exclude *.o DIRECTORY
- * You must use use shell syntax, or globbing, rather than `regexp'
- syntax, when using exclude options in `tar'. If you try to use
- `regexp' syntax to describe files to be excluded, your command
+ * You must use use shell syntax, or globbing, rather than 'regexp'
+ syntax, when using exclude options in 'tar'. If you try to use
+ 'regexp' syntax to describe files to be excluded, your command
might fail.
- * In earlier versions of `tar', what is now the `--exclude-from'
- option was called `--exclude' instead. Now, `--exclude' applies
- to patterns listed on the command line and `--exclude-from'
- applies to patterns listed in a file.
-
+ *
+ In earlier versions of 'tar', what is now the '--exclude-from'
+ option was called '--exclude' instead. Now, '--exclude' applies to
+ patterns listed on the command line and '--exclude-from' applies to
+ patterns listed in a file.
\1f
File: tar.info, Node: wildcards, Next: quoting styles, Prev: exclude, Up: Choosing
6.5 Wildcards Patterns and Matching
===================================
-"Globbing" is the operation by which "wildcard" characters, `*' or `?'
+"Globbing" is the operation by which "wildcard" characters, '*' or '?'
for example, are replaced and expanded into all existing files matching
-the given pattern. GNU `tar' can use wildcard patterns for matching
-(or globbing) archive members when extracting from or listing an
-archive. Wildcard patterns are also used for verifying volume labels
-of `tar' archives. This section has the purpose of explaining wildcard
-syntax for `tar'.
+the given pattern. GNU 'tar' can use wildcard patterns for matching (or
+globbing) archive members when extracting from or listing an archive.
+Wildcard patterns are also used for verifying volume labels of 'tar'
+archives. This section has the purpose of explaining wildcard syntax
+for 'tar'.
A PATTERN should be written according to shell syntax, using wildcard
-characters to effect globbing. Most characters in the pattern stand
-for themselves in the matched string, and case is significant: `a' will
-match only `a', and not `A'. The character `?' in the pattern matches
-any single character in the matched string. The character `*' in the
+characters to effect globbing. Most characters in the pattern stand for
+themselves in the matched string, and case is significant: 'a' will
+match only 'a', and not 'A'. The character '?' in the pattern matches
+any single character in the matched string. The character '*' in the
pattern matches zero, one, or more single characters in the matched
-string. The character `\' says to take the following character of the
-pattern _literally_; it is useful when one needs to match the `?', `*',
-`[' or `\' characters, themselves.
+string. The character '\' says to take the following character of the
+pattern _literally_; it is useful when one needs to match the '?', '*',
+'[' or '\' characters, themselves.
- The character `[', up to the matching `]', introduces a character
+ The character '[', up to the matching ']', introduces a character
class. A "character class" is a list of acceptable characters for the
-next single character of the matched string. For example, `[abcde]'
+next single character of the matched string. For example, '[abcde]'
would match any of the first five letters of the alphabet. Note that
within a character class, all of the "special characters" listed above
-other than `\' lose their special meaning; for example, `[-\\[*?]]'
-would match any of the characters, `-', `\', `[', `*', `?', or `]'.
-(Due to parsing constraints, the characters `-' and `]' must either
-come _first_ or _last_ in a character class.)
+other than '\' lose their special meaning; for example, '[-\\[*?]]'
+would match any of the characters, '-', '\', '[', '*', '?', or ']'.
+(Due to parsing constraints, the characters '-' and ']' must either come
+_first_ or _last_ in a character class.)
- If the first character of the class after the opening `[' is `!' or
-`^', then the meaning of the class is reversed. Rather than listing
+ If the first character of the class after the opening '[' is '!' or
+'^', then the meaning of the class is reversed. Rather than listing
character to match, it lists those characters which are _forbidden_ as
the next single character of the matched string.
Other characters of the class stand for themselves. The special
-construction `[A-E]', using an hyphen between two letters, is meant to
+construction '[A-E]', using an hyphen between two letters, is meant to
represent all characters between A and E, inclusive.
- Periods (`.') or forward slashes (`/') are not considered special
-for wildcard matches. However, if a pattern completely matches a
-directory prefix of a matched string, then it matches the full matched
-string: thus, excluding a directory also excludes all the files beneath
-it.
+ Periods ('.') or forward slashes ('/') are not considered special for
+wildcard matches. However, if a pattern completely matches a directory
+prefix of a matched string, then it matches the full matched string:
+thus, excluding a directory also excludes all the files beneath it.
* Menu:
Controlling Pattern-Matching
----------------------------
-For the purposes of this section, we call "exclusion members" all
-member names obtained while processing `--exclude' and `--exclude-from'
+For the purposes of this section, we call "exclusion members" all member
+names obtained while processing '--exclude' and '--exclude-from'
options, and "inclusion members" those member names that were given in
-the command line or read from the file specified with `--files-from'
+the command line or read from the file specified with '--files-from'
option.
These two pairs of member lists are used in the following operations:
-`--diff', `--extract', `--list', `--update'.
+'--diff', '--extract', '--list', '--update'.
- There are no inclusion members in create mode (`--create' and
-`--append'), since in this mode the names obtained from the command
-line refer to _files_, not archive members.
+ There are no inclusion members in create mode ('--create' and
+'--append'), since in this mode the names obtained from the command line
+refer to _files_, not archive members.
By default, inclusion members are compared with archive members
literally (1) and exclusion members are treated as globbing patterns.
This behavior can be altered by using the following options:
-`--wildcards'
+'--wildcards'
Treat all member names as wildcards.
-`--no-wildcards'
+'--no-wildcards'
Treat all member names as literal strings.
- Thus, to extract files whose names end in `.c', you can use:
+ Thus, to extract files whose names end in '.c', you can use:
$ tar -xf foo.tar -v --wildcards '*.c'
a.c
Notice quoting of the pattern to prevent the shell from interpreting it.
- The effect of `--wildcards' option is canceled by `--no-wildcards'.
-This can be used to pass part of the command line arguments verbatim
-and other part as globbing patterns. For example, the following
-invocation:
+ The effect of '--wildcards' option is canceled by '--no-wildcards'.
+This can be used to pass part of the command line arguments verbatim and
+other part as globbing patterns. For example, the following invocation:
$ tar -xf foo.tar --wildcards '*.txt' --no-wildcards '[remarks]'
-instructs `tar' to extract from `foo.tar' all files whose names end in
-`.txt' and the file named `[remarks]'.
+instructs 'tar' to extract from 'foo.tar' all files whose names end in
+'.txt' and the file named '[remarks]'.
Normally, a pattern matches a name if an initial subsequence of the
-name's components matches the pattern, where `*', `?', and `[...]' are
-the usual shell wildcards, `\' escapes wildcards, and wildcards can
-match `/'.
+name's components matches the pattern, where '*', '?', and '[...]' are
+the usual shell wildcards, '\' escapes wildcards, and wildcards can
+match '/'.
- Other than optionally stripping leading `/' from names (*note
+ Other than optionally stripping leading '/' from names (*note
absolute::), patterns and names are used as-is. For example, trailing
-`/' is not trimmed from a user-specified name before deciding whether
-to exclude it.
+'/' is not trimmed from a user-specified name before deciding whether to
+exclude it.
However, this matching procedure can be altered by the options listed
below. These options accumulate. For example:
--ignore-case --exclude='makefile' --no-ignore-case ---exclude='readme'
-ignores case when excluding `makefile', but not when excluding `readme'.
+ignores case when excluding 'makefile', but not when excluding 'readme'.
-`--anchored'
-`--no-anchored'
+'--anchored'
+'--no-anchored'
If anchored, a pattern must match an initial subsequence of the
name's components. Otherwise, the pattern can match any
- subsequence. Default is `--no-anchored' for exclusion members and
- `--anchored' inclusion members.
+ subsequence. Default is '--no-anchored' for exclusion members and
+ '--anchored' inclusion members.
-`--ignore-case'
-`--no-ignore-case'
+'--ignore-case'
+'--no-ignore-case'
When ignoring case, upper-case patterns match lower-case names and
vice versa. When not ignoring case (the default), matching is
case-sensitive.
-`--wildcards-match-slash'
-`--no-wildcards-match-slash'
+'--wildcards-match-slash'
+'--no-wildcards-match-slash'
When wildcards match slash (the default for exclusion members), a
- wildcard like `*' in the pattern can match a `/' in the name.
- Otherwise, `/' is matched only by `/'.
-
+ wildcard like '*' in the pattern can match a '/' in the name.
+ Otherwise, '/' is matched only by '/'.
- The `--recursion' and `--no-recursion' options (*note recurse::)
-also affect how member patterns are interpreted. If recursion is in
-effect, a pattern matches a name if it matches any of the name's parent
+ The '--recursion' and '--no-recursion' options (*note recurse::) also
+affect how member patterns are interpreted. If recursion is in effect,
+a pattern matches a name if it matches any of the name's parent
directories.
The following table summarizes pattern-matching default values:
Members Default settings
---------------------------------------------------------------------------
-Inclusion `--no-wildcards --anchored
+--------------------------------------------------------------------------
+Inclusion '--no-wildcards --anchored
--no-wildcards-match-slash'
-Exclusion `--wildcards --no-anchored
+Exclusion '--wildcards --no-anchored
--wildcards-match-slash'
---------- Footnotes ----------
- (1) Notice that earlier GNU `tar' versions used globbing for
+ (1) Notice that earlier GNU 'tar' versions used globbing for
inclusion members, which contradicted to UNIX98 specification and was
-not documented. *Note Changes::, for more information on this and other
+not documented. *Note Changes::, for more information on this and other
changes.
\1f
6.6 Quoting Member Names
========================
-When displaying member names, `tar' takes care to avoid ambiguities
+When displaying member names, 'tar' takes care to avoid ambiguities
caused by certain characters. This is called "name quoting". The
characters in question are:
* Non-printable control characters:
- Character ASCII Character name
- ---------------------------------------------------------------
- \a 7 Audible bell
- \b 8 Backspace
- \f 12 Form feed
- \n 10 New line
- \r 13 Carriage return
- \t 9 Horizontal tabulation
- \v 11 Vertical tabulation
+ Character ASCII Character name
+ -------------------------------------------------------------------
+ \a 7 Audible bell
+ \b 8 Backspace
+ \f 12 Form feed
+ \n 10 New line
+ \r 13 Carriage return
+ \t 9 Horizontal tabulation
+ \v 11 Vertical tabulation
* Space (ASCII 32)
- * Single and double quotes (`'' and `"')
+ * Single and double quotes (''' and '"')
- * Backslash (`\')
+ * Backslash ('\')
- The exact way `tar' uses to quote these characters depends on the
+ The exact way 'tar' uses to quote these characters depends on the
"quoting style". The default quoting style, called "escape" (see
below), uses backslash notation to represent control characters, space
and backslash. Using this quoting style, control characters are
-represented as listed in column `Character' in the above table, a space
-is printed as `\ ' and a backslash as `\\'.
+represented as listed in column 'Character' in the above table, a space
+is printed as '\ ' and a backslash as '\\'.
- GNU `tar' offers seven distinct quoting styles, which can be selected
-using `--quoting-style' option:
+ GNU 'tar' offers seven distinct quoting styles, which can be selected
+using '--quoting-style' option:
+
+'--quoting-style=STYLE'
-`--quoting-style=STYLE'
Sets quoting style. Valid values for STYLE argument are: literal,
shell, shell-always, c, escape, locale, clocale.
These styles are described in detail below. To illustrate their
-effect, we will use an imaginary tar archive `arch.tar' containing the
+effect, we will use an imaginary tar archive 'arch.tar' containing the
following members:
# 1. Contains horizontal tabulation character.
# 6. Contains a backslash character:
a\backslash
- Here is how usual `ls' command would have listed them, if they had
+ Here is how usual 'ls' command would have listed them, if they had
existed in the current working directory:
$ ls
Quoting styles:
-`literal'
+'literal'
No quoting, display each character as is:
$ tar tf arch.tar --quoting-style=literal
./a
newline
-`shell'
+'shell'
Display characters the same way Bourne shell does: control
- characters, except `\t' and `\n', are printed using backslash
- escapes, `\t' and `\n' are printed as is, and a single quote is
- printed as `\''. If a name contains any quoted characters, it is
+ characters, except '\t' and '\n', are printed using backslash
+ escapes, '\t' and '\n' are printed as is, and a single quote is
+ printed as '\''. If a name contains any quoted characters, it is
enclosed in single quotes. In particular, if a name contains
single quotes, it is printed as several single-quoted strings:
'./a
newline'
-`shell-always'
- Same as `shell', but the names are always enclosed in single
+'shell-always'
+ Same as 'shell', but the names are always enclosed in single
quotes:
$ tar tf arch.tar --quoting-style=shell-always
'./a
newline'
-`c'
+'c'
Use the notation of the C programming language. All names are
enclosed in double quotes. Control characters are quoted using
- backslash notations, double quotes are represented as `\"',
- backslash characters are represented as `\\'. Single quotes and
+ backslash notations, double quotes are represented as '\"',
+ backslash characters are represented as '\\'. Single quotes and
spaces are not quoted:
$ tar tf arch.tar --quoting-style=c
"./a\ttab"
"./a\nnewline"
-`escape'
+'escape'
Control characters are printed using backslash notation, a space is
- printed as `\ ' and a backslash as `\\'. This is the default
+ printed as '\ ' and a backslash as '\\'. This is the default
quoting style, unless it was changed when configured the package.
$ tar tf arch.tar --quoting-style=escape
./a\ttab
./a\nnewline
-`locale'
+'locale'
Control characters, single quote and backslash are printed using
backslash notation. All names are quoted using left and right
quotation marks, appropriate to the current locale. If it does not
- define quotation marks, use `'' as left and as right quotation
+ define quotation marks, use ''' as left and as right quotation
marks. Any occurrences of the right quotation mark in a name are
- escaped with `\', for example:
+ escaped with '\', for example:
For example:
'./a\ttab'
'./a\nnewline'
-`clocale'
- Same as `locale', but `"' is used for both left and right
- quotation marks, if not provided by the currently selected locale:
+'clocale'
+ Same as 'locale', but '"' is used for both left and right quotation
+ marks, if not provided by the currently selected locale:
$ tar tf arch.tar --quoting-style=clocale
"./"
You can specify which characters should be quoted in addition to
those implied by the current quoting style:
-`--quote-chars=STRING'
+'--quote-chars=STRING'
Always quote characters from STRING, even if the selected quoting
style would not quote them.
- For example, using `escape' quoting (compare with the usual escape
+ For example, using 'escape' quoting (compare with the usual escape
listing above):
$ tar tf arch.tar --quoting-style=escape --quote-chars=' "'
To disable quoting of such additional characters, use the following
option:
-`--no-quote-chars=STRING'
+'--no-quote-chars=STRING'
Remove characters listed in STRING from the list of quoted
- characters set by the previous `--quote-chars' option.
+ characters set by the previous '--quote-chars' option.
- This option is particularly useful if you have added `--quote-chars'
-to your `TAR_OPTIONS' (*note TAR_OPTIONS::) and wish to disable it for
+ This option is particularly useful if you have added '--quote-chars'
+to your 'TAR_OPTIONS' (*note TAR_OPTIONS::) and wish to disable it for
the current invocation.
- Note, that `--no-quote-chars' does _not_ disable those characters
+ Note, that '--no-quote-chars' does _not_ disable those characters
that are quoted by default in the selected quoting style.
\1f
6.7 Modifying File and Member Names
===================================
-`Tar' archives contain detailed information about files stored in them
+'Tar' archives contain detailed information about files stored in them
and full file names are part of that information. When storing a file
to an archive, its file name is recorded in it, along with the actual
file contents. When restoring from an archive, a file is created on
However, there are some cases when it is not.
First of all, it is often unsafe to extract archive members with
-absolute file names or those that begin with a `../'. GNU `tar' takes
+absolute file names or those that begin with a '../'. GNU 'tar' takes
special precautions when extracting such names and provides a special
option for handling them, which is described in *note absolute::.
directory components, or with otherwise modified names. In other cases
it is desirable to store files under differing names in the archive.
- GNU `tar' provides several options for these needs.
+ GNU 'tar' provides several options for these needs.
-`--strip-components=NUMBER'
+'--strip-components=NUMBER'
Strip given NUMBER of leading components from file names before
extraction.
- For example, suppose you have archived whole `/usr' hierarchy to a
-tar archive named `usr.tar'. Among other files, this archive contains
-`usr/include/stdlib.h', which you wish to extract to the current
-working directory. To do so, you type:
+ For example, suppose you have archived whole '/usr' hierarchy to a
+tar archive named 'usr.tar'. Among other files, this archive contains
+'usr/include/stdlib.h', which you wish to extract to the current working
+directory. To do so, you type:
$ tar -xf usr.tar --strip=2 usr/include/stdlib.h
- The option `--strip=2' instructs `tar' to strip the two leading
-components (`usr/' and `include/') off the file name.
+ The option '--strip=2' instructs 'tar' to strip the two leading
+components ('usr/' and 'include/') off the file name.
- If you add the `--verbose' (`-v') option to the invocation above,
-you will note that the verbose listing still contains the full file
-name, with the two removed components still in place. This can be
-inconvenient, so `tar' provides a special option for altering this
+ If you add the '--verbose' ('-v') option to the invocation above, you
+will note that the verbose listing still contains the full file name,
+with the two removed components still in place. This can be
+inconvenient, so 'tar' provides a special option for altering this
behavior:
-`--show-transformed-names'
+'--show-transformed-names'
Display file or member names with all requested transformations
applied.
$ tar -xf usr.tar -v --strip=2 --show-transformed usr/include/stdlib.h
stdlib.h
- Notice that in both cases the file `stdlib.h' is extracted to the
-current working directory, `--show-transformed-names' affects only the
+ Notice that in both cases the file 'stdlib.h' is extracted to the
+current working directory, '--show-transformed-names' affects only the
way its name is displayed.
This option is especially useful for verifying whether the invocation
to make sure the command will produce the intended results.
In case you need to apply more complex modifications to the file
-name, GNU `tar' provides a general-purpose transformation option:
+name, GNU 'tar' provides a general-purpose transformation option:
-`--transform=EXPRESSION'
-`--xform=EXPRESSION'
+'--transform=EXPRESSION'
+'--xform=EXPRESSION'
Modify file names using supplied EXPRESSION.
-The EXPRESSION is a `sed'-like replace expression of the form:
+The EXPRESSION is a 'sed'-like replace expression of the form:
s/REGEXP/REPLACE/[FLAGS]
each file name part that matches REGEXP. Both REGEXP and REPLACE are
described in detail in *note The "s" Command: (sed)The "s" Command.
- Any delimiter can be used in lieu of `/', the only requirement being
-that it be used consistently throughout the expression. For example,
+ Any delimiter can be used in lieu of '/', the only requirement being
+that it be used consistently throughout the expression. For example,
the following two expressions are equivalent:
s/one/two/
s,one,two,
Changing delimiters is often useful when the REGEX contains slashes.
-For example, it is more convenient to write `s,/,-,' than `s/\//-/'.
+For example, it is more convenient to write 's,/,-,' than 's/\//-/'.
- As in `sed', you can give several replace expressions, separated by
-a semicolon.
+ As in 'sed', you can give several replace expressions, separated by a
+semicolon.
Supported FLAGS are:
-`g'
+'g'
Apply the replacement to _all_ matches to the REGEXP, not just the
first.
-`i'
+'i'
Use case-insensitive matching.
-`x'
+'x'
REGEXP is an "extended regular expression" (*note Extended regular
expressions: (sed)Extended regexps.).
-`NUMBER'
+'NUMBER'
Only replace the NUMBERth match of the REGEXP.
Note: the POSIX standard does not specify what should happen when
- you mix the `g' and NUMBER modifiers. GNU `tar' follows the GNU
- `sed' implementation in this regard, so the interaction is defined
+ you mix the 'g' and NUMBER modifiers. GNU 'tar' follows the GNU
+ 'sed' implementation in this regard, so the interaction is defined
to be: ignore matches before the NUMBERth, and then match and
replace all matches from the NUMBERth on.
+ In addition, several "transformation scope" flags are supported, that
+control to what files transformations apply. These are:
- In addition, several "transformation scope" flags are supported,
-that control to what files transformations apply. These are:
-
-`r'
+'r'
Apply transformation to regular archive members.
-`R'
+'R'
Do not apply transformation to regular archive members.
-`s'
+'s'
Apply transformation to symbolic link targets.
-`S'
+'S'
Do not apply transformation to symbolic link targets.
-`h'
+'h'
Apply transformation to hard link targets.
-`H'
+'H'
Do not apply transformation to hard link targets.
- Default is `rsh', which means to apply tranformations to both archive
-members and targets of symbolic and hard links.
+ Default is 'rsh', which means to apply transformations to both
+archive members and targets of symbolic and hard links.
- Default scope flags can also be changed using `flags=' statement in
+ Default scope flags can also be changed using 'flags=' statement in
the transform expression. The flags set this way remain in force until
-next `flags=' statement or end of expression, whichever occurs first.
+next 'flags=' statement or end of expression, whichever occurs first.
For example:
--transform 'flags=S;s|^|/usr/local/|'
- Here are several examples of `--transform' usage:
+ Here are several examples of '--transform' usage:
- 1. Extract `usr/' hierarchy into `usr/local/':
+ 1. Extract 'usr/' hierarchy into 'usr/local/':
$ tar --transform='s,usr/,usr/local/,' -x -f arch.tar
2. Strip two leading directory components (equivalent to
- `--strip-components=2'):
+ '--strip-components=2'):
$ tar --transform='s,/*[^/]*/[^/]*/,,' -x -f arch.tar
$ tar --transform 's/.*/\L&/' -x -f arch.tar
- 4. Prepend `/prefix/' to each file name:
+ 4. Prepend '/prefix/' to each file name:
$ tar --transform 's,^,/prefix/,' -x -f arch.tar
- 5. Archive the `/lib' directory, prepending `/usr/local' to each
+ 5. Archive the '/lib' directory, prepending '/usr/local' to each
archive member:
$ tar --transform 's,^,/usr/local/,S' -c -f arch.tar /lib
- Notice the use of flags in the last example. The `/lib' directory
-often contains many symbolic links to files within it. It may look,
-for example, like this:
+ Notice the use of flags in the last example. The '/lib' directory
+often contains many symbolic links to files within it. It may look, for
+example, like this:
$ ls -l
drwxr-xr-x root/root 0 2008-07-08 16:20 /lib/
lrwxrwxrwx root/root 0 2008-06-24 17:12 /lib/libc.so.6 -> libc-2.3.2.so
...
- Using the expression `s,^,/usr/local/,' would mean adding
-`/usr/local' to both regular archive members and to link targets. In
-this case, `/lib/libc.so.6' would become:
+ Using the expression 's,^,/usr/local/,' would mean adding
+'/usr/local' to both regular archive members and to link targets. In
+this case, '/lib/libc.so.6' would become:
/usr/local/lib/libc.so.6 -> /usr/local/libc-2.3.2.so
- This is definitely not desired. To avoid this, the `S' flag is
-used, which excludes symbolic link targets from filename
-transformations. The result is:
+ This is definitely not desired. To avoid this, the 'S' flag is used,
+which excludes symbolic link targets from filename transformations. The
+result is:
$ tar --transform 's,^,/usr/local/,S', -c -v -f arch.tar \
--show-transformed /lib
lrwxrwxrwx root/root 0 2008-06-24 17:12 /usr/local/lib/libc.so.6 \
-> libc-2.3.2.so
- Unlike `--strip-components', `--transform' can be used in any GNU
-`tar' operation mode. For example, the following command adds files to
-the archive while replacing the leading `usr/' component with `var/':
+ Unlike '--strip-components', '--transform' can be used in any GNU
+'tar' operation mode. For example, the following command adds files to
+the archive while replacing the leading 'usr/' component with 'var/':
$ tar -cf arch.tar --transform='s,^usr/,var/,' /
- To test `--transform' effect we suggest using
-`--show-transformed-names' option:
+ To test '--transform' effect we suggest using
+'--show-transformed-names' option:
$ tar -cf arch.tar --transform='s,^usr/,var/,' \
--verbose --show-transformed-names /
- If both `--strip-components' and `--transform' are used together,
-then `--transform' is applied first, and the required number of
+ If both '--strip-components' and '--transform' are used together,
+then '--transform' is applied first, and the required number of
components is then stripped from its result.
- You can use as many `--transform' options in a single command line
-as you want. The specified expressions will then be applied in order
-of their appearance. For example, the following two invocations are
+ You can use as many '--transform' options in a single command line as
+you want. The specified expressions will then be applied in order of
+their appearance. For example, the following two invocations are
equivalent:
$ tar -cf arch.tar --transform='s,/usr/var,/var/' \
6.8 Operating Only on New Files
===============================
-The `--after-date=DATE' (`--newer=DATE', `-N DATE') option causes `tar'
-to only work on files whose data modification or status change times
-are newer than the DATE given. If DATE starts with `/' or `.', it is
-taken to be a file name; the data modification time of that file is
-used as the date. If you use this option when creating or appending to
-an archive, the archive will only include new files. If you use
-`--after-date' when extracting an archive, `tar' will only extract
-files newer than the DATE you specify.
+The '--after-date=DATE' ('--newer=DATE', '-N DATE') option causes 'tar'
+to only work on files whose data modification or status change times are
+newer than the DATE given. If DATE starts with '/' or '.', it is taken
+to be a file name; the data modification time of that file is used as
+the date. If you use this option when creating or appending to an
+archive, the archive will only include new files. If you use
+'--after-date' when extracting an archive, 'tar' will only extract files
+newer than the DATE you specify.
- If you only want `tar' to make the date comparison based on
+ If you only want 'tar' to make the date comparison based on
modification of the file's data (rather than status changes), then use
-the `--newer-mtime=DATE' option.
+the '--newer-mtime=DATE' option.
You may use these options with any operation. Note that these
-options differ from the `--update' (`-u') operation in that they allow
-you to specify a particular date against which `tar' can compare when
+options differ from the '--update' ('-u') operation in that they allow
+you to specify a particular date against which 'tar' can compare when
deciding whether or not to archive the files.
-`--after-date=DATE'
-`--newer=DATE'
-`-N DATE'
+'--after-date=DATE'
+'--newer=DATE'
+'-N DATE'
Only store files newer than DATE.
Acts on files only if their data modification or status change
times are later than DATE. Use in conjunction with any operation.
- If DATE starts with `/' or `.', it is taken to be a file name; the
+ If DATE starts with '/' or '.', it is taken to be a file name; the
data modification time of that file is used as the date.
-`--newer-mtime=DATE'
- Acts like `--after-date', but only looks at data modification
+'--newer-mtime=DATE'
+ Acts like '--after-date', but only looks at data modification
times.
- These options limit `tar' to operate only on files which have been
+ These options limit 'tar' to operate only on files which have been
modified after the date specified. A file's status is considered to
have changed if its contents have been modified, or if its owner,
permissions, and so forth, have been changed. (For more information on
how to specify a date, see *note Date input formats::; remember that the
entire date argument must be quoted if it contains any spaces.)
- Gurus would say that `--after-date' tests both the data modification
-time (`mtime', the time the contents of the file were last modified)
-and the status change time (`ctime', the time the file's status was
-last changed: owner, permissions, etc.) fields, while `--newer-mtime'
-tests only the `mtime' field.
+ Gurus would say that '--after-date' tests both the data modification
+time ('mtime', the time the contents of the file were last modified) and
+the status change time ('ctime', the time the file's status was last
+changed: owner, permissions, etc.) fields, while '--newer-mtime' tests
+only the 'mtime' field.
- To be precise, `--after-date' checks _both_ `mtime' and `ctime' and
+ To be precise, '--after-date' checks _both_ 'mtime' and 'ctime' and
processes the file if either one is more recent than DATE, while
-`--newer-mtime' only checks `mtime' and disregards `ctime'. Neither
-does it use `atime' (the last time the contents of the file were looked
+'--newer-mtime' only checks 'mtime' and disregards 'ctime'. Neither
+does it use 'atime' (the last time the contents of the file were looked
at).
Date specifiers can have embedded spaces. Because of this, you may
$ tar -cf foo.tar --newer-mtime '2 days ago'
- When any of these options is used with the option `--verbose' (*note
-verbose tutorial::) GNU `tar' will try to convert the specified date
+ When any of these options is used with the option '--verbose' (*note
+verbose tutorial::) GNU 'tar' will try to convert the specified date
back to its textual representation and compare that with the one given
-with the option. If the two dates differ, `tar' will print a warning
+with the option. If the two dates differ, 'tar' will print a warning
saying what date it will use. This is to help user ensure he is using
the right date. For example:
tar: Option --after-date: Treating date '10 days ago' as 2006-06-11
13:19:37.232434
- *Please Note:* `--after-date' and `--newer-mtime' should not be
+ *Please Note:* '--after-date' and '--newer-mtime' should not be
used for incremental backups. *Note Incremental Dumps::, for
proper way of creating incremental backups.
6.9 Descending into Directories
===============================
-Usually, `tar' will recursively explore all directories (either those
-given on the command line or through the `--files-from' option) for the
-various files they contain. However, you may not always want `tar' to
+Usually, 'tar' will recursively explore all directories (either those
+given on the command line or through the '--files-from' option) for the
+various files they contain. However, you may not always want 'tar' to
act this way.
- The `--no-recursion' option inhibits `tar''s recursive descent into
-specified directories. If you specify `--no-recursion', you can use
-the `find' (*note find: (find)Top.) utility for hunting through levels
-of directories to construct a list of file names which you could then
-pass to `tar'. `find' allows you to be more selective when choosing
-which files to archive; see *note files::, for more information on
-using `find' with `tar'.
+ The '--no-recursion' option inhibits 'tar''s recursive descent into
+specified directories. If you specify '--no-recursion', you can use the
+'find' (*note find: (find)Top.) utility for hunting through levels of
+directories to construct a list of file names which you could then pass
+to 'tar'. 'find' allows you to be more selective when choosing which
+files to archive; see *note files::, for more information on using
+'find' with 'tar'.
-`--no-recursion'
- Prevents `tar' from recursively descending directories.
+'--no-recursion'
+ Prevents 'tar' from recursively descending directories.
-`--recursion'
- Requires `tar' to recursively descend directories. This is the
+'--recursion'
+ Requires 'tar' to recursively descend directories. This is the
default.
- When you use `--no-recursion', GNU `tar' grabs directory entries
+ When you use '--no-recursion', GNU 'tar' grabs directory entries
themselves, but does not descend on them recursively. Many people use
-`find' for locating files they want to back up, and since `tar'
+'find' for locating files they want to back up, and since 'tar'
_usually_ recursively descends on directories, they have to use the
-`-not -type d' test in their `find' invocation (*note Type:
+'-not -type d' test in their 'find' invocation (*note Type:
(find)Type.), as they usually do not want all the files in a directory.
-They then use the `--files-from' option to archive the files located
-via `find'.
+They then use the '--files-from' option to archive the files located via
+'find'.
The problem when restoring files archived in this manner is that the
directories themselves are not in the archive; so the
-`--same-permissions' (`--preserve-permissions', `-p') option does not
+'--same-permissions' ('--preserve-permissions', '-p') option does not
affect them--while users might really like it to. Specifying
-`--no-recursion' is a way to tell `tar' to grab only the directory
+'--no-recursion' is a way to tell 'tar' to grab only the directory
entries given to it, adding no new files on its own. To summarize, if
-you use `find' to create a list of files to be stored in an archive,
-use it as follows:
+you use 'find' to create a list of files to be stored in an archive, use
+it as follows:
$ find DIR TESTS | \
tar -cf ARCHIVE -T - --no-recursion
- The `--no-recursion' option also applies when extracting: it causes
-`tar' to extract only the matched directory entries, not the files
-under those directories.
+ The '--no-recursion' option also applies when extracting: it causes
+'tar' to extract only the matched directory entries, not the files under
+those directories.
- The `--no-recursion' option also affects how globbing patterns are
+ The '--no-recursion' option also affects how globbing patterns are
interpreted (*note controlling pattern-matching::).
- The `--no-recursion' and `--recursion' options apply to later
-options and operands, and can be overridden by later occurrences of
-`--no-recursion' and `--recursion'. For example:
+ The '--no-recursion' and '--recursion' options apply to later options
+and operands, and can be overridden by later occurrences of
+'--no-recursion' and '--recursion'. For example:
$ tar -cf jams.tar --no-recursion grape --recursion grape/concord
-creates an archive with one entry for `grape', and the recursive
-contents of `grape/concord', but no entries under `grape' other than
-`grape/concord'.
-
-\1f
-File: tar.info, Node: one, Prev: recurse, Up: Choosing
-
-6.10 Crossing File System Boundaries
-====================================
-
-`tar' will normally automatically cross file system boundaries in order
-to archive files which are part of a directory tree. You can change
-this behavior by running `tar' and specifying `--one-file-system'.
-This option only affects files that are archived because they are in a
-directory that is being archived; `tar' will still archive files
-explicitly named on the command line or through `--files-from',
-regardless of where they reside.
-
-`--one-file-system'
- Prevents `tar' from crossing file system boundaries when
- archiving. Use in conjunction with any write operation.
-
- The `--one-file-system' option causes `tar' to modify its normal
-behavior in archiving the contents of directories. If a file in a
-directory is not on the same file system as the directory itself, then
-`tar' will not archive that file. If the file is a directory itself,
-`tar' will not archive anything beneath it; in other words, `tar' will
-not cross mount points.
-
- This option is useful for making full or incremental archival
-backups of a file system. If this option is used in conjunction with
-`--verbose' (`-v'), files that are excluded are mentioned by name on
-the standard error.
-
-* Menu:
-
-* directory:: Changing Directory
-* absolute:: Absolute File Names
-
-\1f
-File: tar.info, Node: directory, Next: absolute, Up: one
-
-6.10.1 Changing the Working Directory
--------------------------------------
-
-To change the working directory in the middle of a list of file names,
-either on the command line or in a file specified using `--files-from'
-(`-T'), use `--directory' (`-C'). This will change the working
-directory to the specified directory after that point in the list.
-
-`--directory=DIRECTORY'
-`-C DIRECTORY'
- Changes the working directory in the middle of a command line.
-
- For example,
-
- $ tar -c -f jams.tar grape prune -C food cherry
-
-will place the files `grape' and `prune' from the current directory
-into the archive `jams.tar', followed by the file `cherry' from the
-directory `food'. This option is especially useful when you have
-several widely separated files that you want to store in the same
-archive.
-
- Note that the file `cherry' is recorded in the archive under the
-precise name `cherry', _not_ `food/cherry'. Thus, the archive will
-contain three files that all appear to have come from the same
-directory; if the archive is extracted with plain `tar --extract', all
-three files will be written in the current directory.
-
- Contrast this with the command,
-
- $ tar -c -f jams.tar grape prune -C food red/cherry
-
-which records the third file in the archive under the name `red/cherry'
-so that, if the archive is extracted using `tar --extract', the third
-file will be written in a subdirectory named `red'.
-
- You can use the `--directory' option to make the archive independent
-of the original name of the directory holding the files. The following
-command places the files `/etc/passwd', `/etc/hosts', and `/lib/libc.a'
-into the archive `foo.tar':
-
- $ tar -c -f foo.tar -C /etc passwd hosts -C /lib libc.a
-
-However, the names of the archive members will be exactly what they were
-on the command line: `passwd', `hosts', and `libc.a'. They will not
-appear to be related by file name to the original directories where
-those files were located.
-
- Note that `--directory' options are interpreted consecutively. If
-`--directory' specifies a relative file name, it is interpreted
-relative to the then current directory, which might not be the same as
-the original current working directory of `tar', due to a previous
-`--directory' option.
-
- When using `--files-from' (*note files::), you can put various `tar'
-options (including `-C') in the file list. Notice, however, that in
-this case the option and its argument may not be separated by
-whitespace. If you use short option, its argument must either follow
-the option letter immediately, without any intervening whitespace, or
-occupy the next line. Otherwise, if you use long option, separate its
-argument by an equal sign.
-
- For instance, the file list for the above example will be:
-
- -C/etc
- passwd
- hosts
- --directory=/lib
- libc.a
-
-To use it, you would invoke `tar' as follows:
-
- $ tar -c -f foo.tar --files-from list
-
- The interpretation of `--directory' is disabled by `--null' option.
-
-\1f
-File: tar.info, Node: absolute, Prev: directory, Up: one
-
-6.10.2 Absolute File Names
---------------------------
-
-By default, GNU `tar' drops a leading `/' on input or output, and
-complains about file names containing a `..' component. There is an
-option that turns off this behavior:
-
-`--absolute-names'
-`-P'
- Do not strip leading slashes from file names, and permit file names
- containing a `..' file name component.
-
- When `tar' extracts archive members from an archive, it strips any
-leading slashes (`/') from the member name. This causes absolute
-member names in the archive to be treated as relative file names. This
-allows you to have such members extracted wherever you want, instead of
-being restricted to extracting the member in the exact directory named
-in the archive. For example, if the archive member has the name
-`/etc/passwd', `tar' will extract it as if the name were really
-`etc/passwd'.
-
- File names containing `..' can cause problems when extracting, so
-`tar' normally warns you about such files when creating an archive, and
-rejects attempts to extracts such files.
-
- Other `tar' programs do not do this. As a result, if you create an
-archive whose member names start with a slash, they will be difficult
-for other people with a non-GNU `tar' program to use. Therefore, GNU
-`tar' also strips leading slashes from member names when putting
-members into the archive. For example, if you ask `tar' to add the file
-`/bin/ls' to an archive, it will do so, but the member name will be
-`bin/ls'(1).
-
- Symbolic links containing `..' or leading `/' can also cause
-problems when extracting, so `tar' normally extracts them last; it may
-create empty files as placeholders during extraction.
-
- If you use the `--absolute-names' (`-P') option, `tar' will do none
-of these transformations.
-
- To archive or extract files relative to the root directory, specify
-the `--absolute-names' (`-P') option.
-
- Normally, `tar' acts on files relative to the working
-directory--ignoring superior directory names when archiving, and
-ignoring leading slashes when extracting.
-
- When you specify `--absolute-names' (`-P'), `tar' stores file names
-including all superior directory names, and preserves leading slashes.
-If you only invoked `tar' from the root directory you would never need
-the `--absolute-names' option, but using this option may be more
-convenient than switching to root.
-
-`--absolute-names'
- Preserves full file names (including superior directory names) when
- archiving and extracting files.
-
-
- `tar' prints out a message about removing the `/' from file names.
-This message appears once per GNU `tar' invocation. It represents
-something which ought to be told; ignoring what it means can cause very
-serious surprises, later.
-
- Some people, nevertheless, do not want to see this message. Wanting
-to play really dangerously, one may of course redirect `tar' standard
-error to the sink. For example, under `sh':
-
- $ tar -c -f archive.tar /home 2> /dev/null
-
-Another solution, both nicer and simpler, would be to change to the `/'
-directory first, and then avoid absolute notation. For example:
-
- $ tar -c -f archive.tar -C / home
-
- *Note Integrity::, for some of the security-related implications of
-using this option.
-
- ---------- Footnotes ----------
-
- (1) A side effect of this is that when `--create' is used with
-`--verbose' the resulting output is not, generally speaking, the same
-as the one you'd get running `tar --list' command. This may be
-important if you use some scripts for comparing both outputs. *Note
-listing member and file names::, for the information on how to handle
-this case.
-
-\1f
-File: tar.info, Node: Date input formats, Next: Formats, Prev: Choosing, Up: Top
-
-7 Date input formats
-********************
-
-First, a quote:
-
- Our units of temporal measurement, from seconds on up to months,
- are so complicated, asymmetrical and disjunctive so as to make
- coherent mental reckoning in time all but impossible. Indeed, had
- some tyrannical god contrived to enslave our minds to time, to
- make it all but impossible for us to escape subjection to sodden
- routines and unpleasant surprises, he could hardly have done
- better than handing down our present system. It is like a set of
- trapezoidal building blocks, with no vertical or horizontal
- surfaces, like a language in which the simplest thought demands
- ornate constructions, useless particles and lengthy
- circumlocutions. Unlike the more successful patterns of language
- and science, which enable us to face experience boldly or at least
- level-headedly, our system of temporal calculation silently and
- persistently encourages our terror of time.
-
- ... It is as though architects had to measure length in feet,
- width in meters and height in ells; as though basic instruction
- manuals demanded a knowledge of five different languages. It is
- no wonder then that we often look into our own immediate past or
- future, last Tuesday or a week from Sunday, with feelings of
- helpless confusion. ...
-
- --Robert Grudin, `Time and the Art of Living'.
-
- This section describes the textual date representations that GNU
-programs accept. These are the strings you, as a user, can supply as
-arguments to the various programs. The C interface (via the
-`parse_datetime' function) is not described here.
-
-* Menu:
-
-* General date syntax:: Common rules.
-* Calendar date items:: 19 Dec 1994.
-* Time of day items:: 9:20pm.
-* Time zone items:: EST, PDT, UTC, ...
-* Combined date and time of day items:: 1972-09-24T20:02:00,000000-0500.
-* Day of week items:: Monday and others.
-* Relative items in date strings:: next tuesday, 2 years ago.
-* Pure numbers in date strings:: 19931219, 1440.
-* Seconds since the Epoch:: @1078100502.
-* Specifying time zone rules:: TZ="America/New_York", TZ="UTC0".
-* Authors of parse_datetime:: Bellovin, Eggert, Salz, Berets, et al.
-
-\1f
-File: tar.info, Node: General date syntax, Next: Calendar date items, Up: Date input formats
-
-7.1 General date syntax
-=======================
-
-A "date" is a string, possibly empty, containing many items separated
-by whitespace. The whitespace may be omitted when no ambiguity arises.
-The empty string means the beginning of today (i.e., midnight). Order
-of the items is immaterial. A date string may contain many flavors of
-items:
-
- * calendar date items
-
- * time of day items
-
- * time zone items
-
- * combined date and time of day items
-
- * day of the week items
-
- * relative items
-
- * pure numbers.
-
-We describe each of these item types in turn, below.
-
- A few ordinal numbers may be written out in words in some contexts.
-This is most useful for specifying day of the week items or relative
-items (see below). Among the most commonly used ordinal numbers, the
-word `last' stands for -1, `this' stands for 0, and `first' and `next'
-both stand for 1. Because the word `second' stands for the unit of
-time there is no way to write the ordinal number 2, but for convenience
-`third' stands for 3, `fourth' for 4, `fifth' for 5, `sixth' for 6,
-`seventh' for 7, `eighth' for 8, `ninth' for 9, `tenth' for 10,
-`eleventh' for 11 and `twelfth' for 12.
-
- When a month is written this way, it is still considered to be
-written numerically, instead of being "spelled in full"; this changes
-the allowed strings.
-
- In the current implementation, only English is supported for words
-and abbreviations like `AM', `DST', `EST', `first', `January',
-`Sunday', `tomorrow', and `year'.
-
- The output of the `date' command is not always acceptable as a date
-string, not only because of the language problem, but also because
-there is no standard meaning for time zone items like `IST'. When using
-`date' to generate a date string intended to be parsed later, specify a
-date format that is independent of language and that does not use time
-zone items other than `UTC' and `Z'. Here are some ways to do this:
-
- $ LC_ALL=C TZ=UTC0 date
- Mon Mar 1 00:21:42 UTC 2004
- $ TZ=UTC0 date +'%Y-%m-%d %H:%M:%SZ'
- 2004-03-01 00:21:42Z
- $ date --rfc-3339=ns # --rfc-3339 is a GNU extension.
- 2004-02-29 16:21:42.692722128-08:00
- $ date --rfc-2822 # a GNU extension
- Sun, 29 Feb 2004 16:21:42 -0800
- $ date +'%Y-%m-%d %H:%M:%S %z' # %z is a GNU extension.
- 2004-02-29 16:21:42 -0800
- $ date +'@%s.%N' # %s and %N are GNU extensions.
- @1078100502.692722128
-
- Alphabetic case is completely ignored in dates. Comments may be
-introduced between round parentheses, as long as included parentheses
-are properly nested. Hyphens not followed by a digit are currently
-ignored. Leading zeros on numbers are ignored.
-
- Invalid dates like `2005-02-29' or times like `24:00' are rejected.
-In the typical case of a host that does not support leap seconds, a
-time like `23:59:60' is rejected even if it corresponds to a valid leap
-second.
-
-\1f
-File: tar.info, Node: Calendar date items, Next: Time of day items, Prev: General date syntax, Up: Date input formats
-
-7.2 Calendar date items
-=======================
-
-A "calendar date item" specifies a day of the year. It is specified
-differently, depending on whether the month is specified numerically or
-literally. All these strings specify the same calendar date:
-
- 1972-09-24 # ISO 8601.
- 72-9-24 # Assume 19xx for 69 through 99,
- # 20xx for 00 through 68.
- 72-09-24 # Leading zeros are ignored.
- 9/24/72 # Common U.S. writing.
- 24 September 1972
- 24 Sept 72 # September has a special abbreviation.
- 24 Sep 72 # Three-letter abbreviations always allowed.
- Sep 24, 1972
- 24-sep-72
- 24sep72
-
- The year can also be omitted. In this case, the last specified year
-is used, or the current year if none. For example:
-
- 9/24
- sep 24
-
- Here are the rules.
-
- For numeric months, the ISO 8601 format `YEAR-MONTH-DAY' is allowed,
-where YEAR is any positive number, MONTH is a number between 01 and 12,
-and DAY is a number between 01 and 31. A leading zero must be present
-if a number is less than ten. If YEAR is 68 or smaller, then 2000 is
-added to it; otherwise, if YEAR is less than 100, then 1900 is added to
-it. The construct `MONTH/DAY/YEAR', popular in the United States, is
-accepted. Also `MONTH/DAY', omitting the year.
-
- Literal months may be spelled out in full: `January', `February',
-`March', `April', `May', `June', `July', `August', `September',
-`October', `November' or `December'. Literal months may be abbreviated
-to their first three letters, possibly followed by an abbreviating dot.
-It is also permitted to write `Sept' instead of `September'.
-
- When months are written literally, the calendar date may be given as
-any of the following:
-
- DAY MONTH YEAR
- DAY MONTH
- MONTH DAY YEAR
- DAY-MONTH-YEAR
-
- Or, omitting the year:
-
- MONTH DAY
+creates an archive with one entry for 'grape', and the recursive
+contents of 'grape/concord', but no entries under 'grape' other than
+'grape/concord'.
projects / debian / tar / blobdiff