This is tar.info, produced by makeinfo version 4.13 from tar.texi.
-This manual is for GNU `tar' (version 1.21, 30 October 2008), which
+This manual is for GNU `tar' (version 1.27, 24 September 2013), which
creates and extracts files from archives.
- Copyright (C) 1992, 1994, 1995, 1996, 1997, 1999, 2000, 2001, 2003,
-2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
+ Copyright (C) 1992, 1994-1997, 1999-2001, 2003-2013 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 1.1 or any later version published by the Free Software
- Foundation; with no Invariant Sections, 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".
+ 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. Buying copies from the FSF supports
- it in developing GNU and promoting software freedom."
+ and modify this GNU manual."
INFO-DIR-SECTION Archiving
START-INFO-DIR-ENTRY
* tar: (tar)tar invocation. Invoking GNU `tar'.
END-INFO-DIR-ENTRY
+\1f
+File: tar.info, Node: Relative items in date strings, Next: Pure numbers in date strings, Prev: Day of week items, Up: Date input formats
+
+7.7 Relative items in date strings
+==================================
+
+"Relative items" adjust a date (or the current date if none) forward or
+backward. The effects of relative items accumulate. Here are some
+examples:
+
+ 1 year
+ 1 year ago
+ 3 years
+ 2 days
+
+ The unit of time displacement may be selected by the string `year'
+or `month' for moving by whole years or months. These are fuzzy units,
+as years and months are not all of equal duration. More precise units
+are `fortnight' which is worth 14 days, `week' worth 7 days, `day'
+worth 24 hours, `hour' worth 60 minutes, `minute' or `min' worth 60
+seconds, and `second' or `sec' worth one second. An `s' suffix on
+these units is accepted and ignored.
+
+ The unit of time may be preceded by a multiplier, given as an
+optionally signed number. Unsigned numbers are taken as positively
+signed. No number at all implies 1 for a multiplier. Following a
+relative item by the string `ago' is equivalent to preceding the unit
+by a multiplier with value -1.
+
+ The string `tomorrow' is worth one day in the future (equivalent to
+`day'), the string `yesterday' is worth one day in the past (equivalent
+to `day ago').
+
+ The strings `now' or `today' are relative items corresponding to
+zero-valued time displacement, these strings come from the fact a
+zero-valued time displacement represents the current time when not
+otherwise changed by previous items. They may be used to stress other
+items, like in `12:00 today'. The string `this' also has the meaning
+of a zero-valued time displacement, but is preferred in date strings
+like `this thursday'.
+
+ When a relative item causes the resulting date to cross a boundary
+where the clocks were adjusted, typically for daylight saving time, the
+resulting date and time are adjusted accordingly.
+
+ The fuzz in units can cause problems with relative items. For
+example, `2003-07-31 -1 month' might evaluate to 2003-07-01, because
+2003-06-31 is an invalid date. To determine the previous month more
+reliably, you can ask for the month before the 15th of the current
+month. For example:
+
+ $ date -R
+ Thu, 31 Jul 2003 13:02:39 -0700
+ $ date --date='-1 month' +'Last month was %B?'
+ Last month was July?
+ $ date --date="$(date +%Y-%m-15) -1 month" +'Last month was %B!'
+ Last month was June!
+
+ Also, take care when manipulating dates around clock changes such as
+daylight saving leaps. In a few cases these have added or subtracted
+as much as 24 hours from the clock, so it is often wise to adopt
+universal time by setting the `TZ' environment variable to `UTC0'
+before embarking on calendrical calculations.
+
+\1f
+File: tar.info, Node: Pure numbers in date strings, Next: Seconds since the Epoch, Prev: Relative items in date strings, Up: Date input formats
+
+7.8 Pure numbers in date strings
+================================
+
+The precise interpretation of a pure decimal number depends on the
+context in the date string.
+
+ If the decimal number is of the form YYYYMMDD and no other calendar
+date item (*note Calendar date items::) appears before it in the date
+string, then YYYY is read as the year, MM as the month number and DD as
+the day of the month, for the specified calendar date.
+
+ If the decimal number is of the form HHMM and no other time of day
+item appears before it in the date string, then HH is read as the hour
+of the day and MM as the minute of the hour, for the specified time of
+day. MM can also be omitted.
+
+ If both a calendar date and a time of day appear to the left of a
+number in the date string, but no relative item, then the number
+overrides the year.
+
+\1f
+File: tar.info, Node: Seconds since the Epoch, Next: Specifying time zone rules, Prev: Pure numbers in date strings, Up: Date input formats
+
+7.9 Seconds since the Epoch
+===========================
+
+If you precede a number with `@', it represents an internal time stamp
+as a count of seconds. The number can contain an internal decimal
+point (either `.' or `,'); any excess precision not supported by the
+internal representation is truncated toward minus infinity. Such a
+number cannot be combined with any other date item, as it specifies a
+complete time stamp.
+
+ Internally, computer times are represented as a count of seconds
+since an epoch--a well-defined point of time. On GNU and POSIX
+systems, the epoch is 1970-01-01 00:00:00 UTC, so `@0' represents this
+time, `@1' represents 1970-01-01 00:00:01 UTC, and so forth. GNU and
+most other POSIX-compliant systems support such times as an extension
+to POSIX, using negative counts, so that `@-1' represents 1969-12-31
+23:59:59 UTC.
+
+ Traditional Unix systems count seconds with 32-bit two's-complement
+integers and can represent times from 1901-12-13 20:45:52 through
+2038-01-19 03:14:07 UTC. More modern systems use 64-bit counts of
+seconds with nanosecond subcounts, and can represent all the times in
+the known lifetime of the universe to a resolution of 1 nanosecond.
+
+ On most hosts, these counts ignore the presence of leap seconds.
+For example, on most hosts `@915148799' represents 1998-12-31 23:59:59
+UTC, `@915148800' represents 1999-01-01 00:00:00 UTC, and there is no
+way to represent the intervening leap second 1998-12-31 23:59:60 UTC.
+
+\1f
+File: tar.info, Node: Specifying time zone rules, Next: Authors of parse_datetime, Prev: Seconds since the Epoch, Up: Date input formats
+
+7.10 Specifying time zone rules
+===============================
+
+Normally, dates are interpreted using the rules of the current time
+zone, which in turn are specified by the `TZ' environment variable, or
+by a system default if `TZ' is not set. To specify a different set of
+default time zone rules that apply just to one date, start the date
+with a string of the form `TZ="RULE"'. The two quote characters (`"')
+must be present in the date, and any quotes or backslashes within RULE
+must be escaped by a backslash.
+
+ For example, with the GNU `date' command you can answer the question
+"What time is it in New York when a Paris clock shows 6:30am on October
+31, 2004?" by using a date beginning with `TZ="Europe/Paris"' as shown
+in the following shell transcript:
+
+ $ export TZ="America/New_York"
+ $ date --date='TZ="Europe/Paris" 2004-10-31 06:30'
+ Sun Oct 31 01:30:00 EDT 2004
+
+ In this example, the `--date' operand begins with its own `TZ'
+setting, so the rest of that operand is processed according to
+`Europe/Paris' rules, treating the string `2004-10-31 06:30' as if it
+were in Paris. However, since the output of the `date' command is
+processed according to the overall time zone rules, it uses New York
+time. (Paris was normally six hours ahead of New York in 2004, but
+this example refers to a brief Halloween period when the gap was five
+hours.)
+
+ A `TZ' value is a rule that typically names a location in the `tz'
+database (http://www.twinsun.com/tz/tz-link.htm). A recent catalog of
+location names appears in the TWiki Date and Time Gateway
+(http://twiki.org/cgi-bin/xtra/tzdate). A few non-GNU hosts require a
+colon before a location name in a `TZ' setting, e.g.,
+`TZ=":America/New_York"'.
+
+ The `tz' database includes a wide variety of locations ranging from
+`Arctic/Longyearbyen' to `Antarctica/South_Pole', but if you are at sea
+and have your own private time zone, or if you are using a non-GNU host
+that does not support the `tz' database, you may need to use a POSIX
+rule instead. Simple POSIX rules like `UTC0' specify a time zone
+without daylight saving time; other rules can specify simple daylight
+saving regimes. *Note Specifying the Time Zone with `TZ': (libc)TZ
+Variable.
+
+\1f
+File: tar.info, Node: Authors of parse_datetime, Prev: Specifying time zone rules, Up: Date input formats
+
+7.11 Authors of `parse_datetime'
+================================
+
+`parse_datetime' started life as `getdate', as originally implemented
+by Steven M. Bellovin (<smb@research.att.com>) while at the University
+of North Carolina at Chapel Hill. The code was later tweaked by a
+couple of people on Usenet, then completely overhauled by Rich $alz
+(<rsalz@bbn.com>) and Jim Berets (<jberets@bbn.com>) in August, 1990.
+Various revisions for the GNU system were made by David MacKenzie, Jim
+Meyering, Paul Eggert and others, including renaming it to `get_date' to
+avoid a conflict with the alternative Posix function `getdate', and a
+later rename to `parse_datetime'. The Posix function `getdate' can
+parse more locale-specific dates using `strptime', but relies on an
+environment variable and external file, and lacks the thread-safety of
+`parse_datetime'.
+
+ This chapter was originally produced by Franc,ois Pinard
+(<pinard@iro.umontreal.ca>) from the `parse_datetime.y' source code,
+and then edited by K. Berry (<kb@cs.umb.edu>).
+
+\1f
+File: tar.info, Node: Formats, Next: Media, Prev: Date input formats, Up: Top
+
+8 Controlling the Archive Format
+********************************
+
+Due to historical reasons, there are several formats of tar archives.
+All of them are based on the same principles, but have some subtle
+differences that often make them incompatible with each other.
+
+ GNU tar is able to create and handle archives in a variety of
+formats. The most frequently used formats are (in alphabetical order):
+
+gnu
+ Format used by GNU `tar' versions up to 1.13.25. This format
+ derived from an early POSIX standard, adding some improvements
+ such as sparse file handling and incremental archives.
+ Unfortunately these features were implemented in a way
+ incompatible with other archive formats.
+
+ Archives in `gnu' format are able to hold file names of unlimited
+ length.
+
+oldgnu
+ Format used by GNU `tar' of versions prior to 1.12.
+
+v7
+ Archive format, compatible with the V7 implementation of tar. This
+ format imposes a number of limitations. The most important of them
+ are:
+
+ 1. The maximum length of a file name is limited to 99 characters.
+
+ 2. The maximum length of a symbolic link is limited to 99
+ characters.
+
+ 3. It is impossible to store special files (block and character
+ devices, fifos etc.)
+
+ 4. Maximum value of user or group ID is limited to 2097151
+ (7777777 octal)
+
+ 5. V7 archives do not contain symbolic ownership information
+ (user and group name of the file owner).
+
+ This format has traditionally been used by Automake when producing
+ Makefiles. This practice will change in the future, in the
+ meantime, however this means that projects containing file names
+ more than 99 characters long will not be able to use GNU `tar'
+ 1.27 and Automake prior to 1.9.
+
+ustar
+ Archive format defined by POSIX.1-1988 specification. It stores
+ symbolic ownership information. It is also able to store special
+ files. However, it imposes several restrictions as well:
+
+ 1. The maximum length of a file name is limited to 256
+ characters, provided that the file name can be split at a
+ directory separator in two parts, first of them being at most
+ 155 bytes long. So, in most cases the maximum file name
+ length will be shorter than 256 characters.
+
+ 2. The maximum length of a symbolic link name is limited to 100
+ characters.
+
+ 3. Maximum size of a file the archive is able to accommodate is
+ 8GB
+
+ 4. Maximum value of UID/GID is 2097151.
+
+ 5. Maximum number of bits in device major and minor numbers is
+ 21.
+
+star
+ Format used by Jo"rg Schilling `star' implementation. GNU `tar'
+ is able to read `star' archives but currently does not produce
+ them.
+
+posix
+ Archive format defined by POSIX.1-2001 specification. This is the
+ most flexible and feature-rich format. It does not impose any
+ restrictions on file sizes or file name lengths. This format is
+ quite recent, so not all tar implementations are able to handle it
+ properly. However, this format is designed in such a way that any
+ tar implementation able to read `ustar' archives will be able to
+ read most `posix' archives as well, with the only exception that
+ any additional information (such as long file names etc.) will in
+ such case be extracted as plain text files along with the files it
+ refers to.
+
+ This archive format will be the default format for future versions
+ of GNU `tar'.
+
+
+ The following table summarizes the limitations of each of these
+formats:
+
+Format UID File Size File Name Devn
+--------------------------------------------------------------------
+gnu 1.8e19 Unlimited Unlimited 63
+oldgnu 1.8e19 Unlimited Unlimited 63
+v7 2097151 8GB 99 n/a
+ustar 2097151 8GB 256 21
+posix Unlimited Unlimited Unlimited Unlimited
+
+ The default format for GNU `tar' is defined at compilation time.
+You may check it by running `tar --help', and examining the last lines
+of its output. Usually, GNU `tar' is configured to create archives in
+`gnu' format, however, future version will switch to `posix'.
+
+* Menu:
+
+* Compression:: Using Less Space through Compression
+* Attributes:: Handling File Attributes
+* Portability:: Making `tar' Archives More Portable
+* cpio:: Comparison of `tar' and `cpio'
+
+\1f
+File: tar.info, Node: Compression, Next: Attributes, Up: Formats
+
+8.1 Using Less Space through Compression
+========================================
+
+* Menu:
+
+* gzip:: Creating and Reading Compressed Archives
+* sparse:: Archiving Sparse Files
+
\1f
File: tar.info, Node: gzip, Next: sparse, Up: Compression
----------------------------------------------
GNU `tar' is able to create and read compressed archives. It supports
-`gzip', `bzip2', `lzma' and `lzop' compression programs. For backward
-compatibility, it also supports `compress' command, although we
-strongly recommend against using it, because it is by far less
-effective than other compression programs(1).
+a wide variety of compression programs, namely: `gzip', `bzip2',
+`lzip', `lzma', `lzop', `xz' and traditional `compress'. The latter is
+supported mostly for backward compatibility, and we recommend against
+using it, because it is by far less effective than the other
+compression programs(1).
Creating a compressed archive is simple: you just specify a
"compression option" along with the usual archive creation commands.
The compression option is `-z' (`--gzip') to create a `gzip' compressed
-archive, `-j' (`--bzip2') to create a `bzip2' compressed archive, `-J'
-(`--lzma') to create an LZMA compressed archive, `--lzop' to create an
-LSOP archive, and `-Z' (`--compress') to use `compress' program. For
-example:
+archive, `-j' (`--bzip2') to create a `bzip2' compressed archive,
+`--lzip' to create an lzip compressed archive, `-J' (`--xz') to create
+an XZ archive, `--lzma' to create an LZMA compressed archive, `--lzop'
+to create an LSOP archive, and `-Z' (`--compress') to use `compress'
+program. For example:
- $ tar cfz archive.tar.gz .
+ $ tar czf archive.tar.gz .
- You can also let GNU `tar' select the compression program basing on
+ You can also let GNU `tar' select the compression program based on
the suffix of the archive file name. This is done using
`--auto-compress' (`-a') command line option. For example, the
following invocation will use `bzip2' for compression:
- $ tar cfa archive.tar.bz2 .
+ $ tar caf archive.tar.bz2 .
whereas the following one will use `lzma':
- $ tar cfa archive.tar.lzma .
+ $ tar caf archive.tar.lzma .
For a complete list of file name suffixes recognized by GNU `tar',
-*note auto-compress::.
+see *note auto-compress::.
Reading compressed archive is even simpler: you don't need to specify
any additional options as GNU `tar' recognizes its format
The format recognition algorithm is based on "signatures", a special
byte sequences in the beginning of file, that are specific for certain
compression formats. If this approach fails, `tar' falls back to using
-archive name suffix to determine its format (*Note auto-compress::, for
+archive name suffix to determine its format (*note auto-compress::, for
a list of recognized suffixes).
+ Some compression programs are able to handle different compression
+formats. GNU `tar' uses this, if the principal decompressor for the
+given format is not available. For example, if `compress' is not
+installed, `tar' will try to use `gzip'. As of version 1.27 the
+following alternatives are tried(2):
+
+Format Main decompressor Alternatives
+---------------------------------------------------------------------
+compress compress gzip
+lzma lzma xz
+bzip2 bzip2 lbzip2
+
The only case when you have to specify a decompression option while
reading the archive is when reading from a pipe or from a tape drive
that does not support random access. However, in this case GNU `tar'
If you see such diagnostics, just add the suggested option to the
invocation of GNU `tar':
- $ cat archive.tar.gz | tar tfz -
+ $ cat archive.tar.gz | tar tzf -
Notice also, that there are several restrictions on operations on
compressed archives. First of all, compressed archives cannot be
-modified, i.e., you cannot update (`--update' (`-u')) them or delete
-(`--delete') members from them or add (`--append' (`-r')) members to
-them. Likewise, you cannot append another `tar' archive to a
-compressed archive using `--concatenate' (`-A')). Secondly,
+modified, i.e., you cannot update (`--update', alias `-u') them or
+delete (`--delete') members from them or add (`--append', alias `-r')
+members to them. Likewise, you cannot append another `tar' archive to
+a compressed archive using `--concatenate' (`-A'). Secondly,
multi-volume archives cannot be compressed.
- The following table summarizes compression options used by GNU `tar'.
+ The following options allow to select a particular compressor
+program:
+
+`-z'
+`--gzip'
+`--ungzip'
+ Filter the archive through `gzip'.
+
+`-J'
+`--xz'
+ Filter the archive through `xz'.
+
+`-j'
+`--bzip2'
+ Filter the archive through `bzip2'.
+
+`--lzip'
+ Filter the archive through `lzip'.
+
+`--lzma'
+ Filter the archive through `lzma'.
+
+`--lzop'
+ Filter the archive through `lzop'.
+
+`-Z'
+`--compress'
+`--uncompress'
+ Filter the archive through `compress'.
+
+ When any of these options is given, GNU `tar' searches the compressor
+binary in the current path and invokes it. The name of the compressor
+program is specified at compilation time using a corresponding
+`--with-COMPNAME' option to `configure', e.g. `--with-bzip2' to select
+a specific `bzip2' binary. *Note lbzip2::, for a detailed discussion.
+
+ The output produced by `tar --help' shows the actual compressor
+names along with each of these options.
+
+ You can use any of these options on physical devices (tape drives,
+etc.) and remote files as well as on normal files; data to or from such
+devices or remote files is reblocked by another copy of the `tar'
+program to enforce the specified (or default) record size. The default
+compression parameters are used. Most compression programs let you
+override these by setting a program-specific environment variable. For
+example, with `gzip' you can set `GZIP':
+
+ $ GZIP='-9 -n' tar czf archive.tar.gz subdir
+ Another way would be to use the `-I' option instead (see below),
+e.g.:
+
+ $ tar -cf archive.tar.gz -I 'gzip -9 -n' subdir
+
+Finally, the third, traditional, way to do this is to use a pipe:
+
+ $ tar cf - subdir | gzip -9 -n > archive.tar.gz
+
+ Compressed archives are easily corrupted, because compressed files
+have little redundancy. The adaptive nature of the compression scheme
+means that the compression tables are implicitly spread all over the
+archive. If you lose a few blocks, the dynamic construction of the
+compression tables becomes unsynchronized, and there is little chance
+that you could recover later in the archive.
+
+ Other compression options provide better control over creating
+compressed archives. These are:
`--auto-compress'
`-a'
`.tz2' `bzip2'
`.tbz2' `bzip2'
`.tbz' `bzip2'
+ `.lz' `lzip'
`.lzma' `lzma'
`.tlz' `lzma'
`.lzo' `lzop'
+ `.xz' `xz'
-`-z'
-`--gzip'
-`--ungzip'
- Filter the archive through `gzip'.
-
- You can use `--gzip' and `--gunzip' on physical devices (tape
- drives, etc.) and remote files as well as on normal files; data to
- or from such devices or remote files is reblocked by another copy
- of the `tar' program to enforce the specified (or default) record
- size. The default compression parameters are used; if you need to
- override them, set `GZIP' environment variable, e.g.:
-
- $ GZIP=--best tar cfz archive.tar.gz subdir
-
- Another way would be to avoid the `--gzip' (`--gunzip',
- `--ungzip', `-z') option and run `gzip' explicitly:
-
- $ tar cf - subdir | gzip --best -c - > archive.tar.gz
-
- About corrupted compressed archives: `gzip''ed files have no
- redundancy, for maximum compression. The adaptive nature of the
- compression scheme means that the compression tables are implicitly
- spread all over the archive. If you lose a few blocks, the dynamic
- construction of the compression tables becomes unsynchronized, and
- there is little chance that you could recover later in the archive.
-
- There are pending suggestions for having a per-volume or per-file
- compression in GNU `tar'. This would allow for viewing the
- contents without decompression, and for resynchronizing
- decompression at every volume or file, in case of corrupted
- archives. Doing so, we might lose some compressibility. But this
- would have make recovering easier. So, there are pros and cons.
- We'll see!
-
-`-j'
-`--bzip2'
- Filter the archive through `bzip2'. Otherwise like `--gzip'.
-
-`--lzma'
-`-J'
- Filter the archive through `lzma'. Otherwise like `--gzip'.
-
-`--lzop'
- Filter the archive through `lzop'. Otherwise like `--gzip'.
+`--use-compress-program=COMMAND'
+`-I=COMMAND'
+ Use external compression program COMMAND. Use this option if you
+ are not happy with the compression program associated with the
+ suffix at compile time or if you have a compression program that
+ GNU `tar' does not support. The COMMAND argument is a valid
+ command invocation, as you would type it at the command line
+ prompt, with any additional options as needed. Enclose it in
+ quotes if it contains white space (see *note Running External
+ Commands: external, for more detail).
-`-Z'
-`--compress'
-`--uncompress'
- Filter the archive through `compress'. Otherwise like `--gzip'.
+ The COMMAND should follow two conventions:
-`--use-compress-program=PROG'
- Use external compression program PROG. Use this option if you
- have a compression program that GNU `tar' does not support. There
- are two requirements to which PROG should comply:
+ First, when invoked without additional options, it should read data
+ from standard input, compress it and output it on standard output.
- First, when called without options, it should read data from
- standard input, compress it and output it on standard output.
+ Secondly, if invoked with the additional `-d' option, it should do
+ exactly the opposite, i.e., read the compressed data from the
+ standard input and produce uncompressed data on the standard
+ output.
- Secondly, if called with `-d' argument, it should do exactly the
- opposite, i.e., read the compressed data from the standard input
- and produce uncompressed data on the standard output.
+ The latter requirement means that you must not use the `-d' option
+ as a part of the COMMAND itself.
The `--use-compress-program' option, in particular, lets you
implement your own filters, not necessarily dealing with
#! /bin/sh
case $1 in
-d) gpg --decrypt - | gzip -d -c;;
- '') gzip -c | gpg -s ;;
+ '') gzip -c | gpg -s;;
*) echo "Unknown option $1">&2; exit 1;;
esac
Then the following command will create a compressed archive signed with
your private key:
- $ tar -cf foo.tar.gpgz --use-compress=gpgz .
+ $ tar -cf foo.tar.gpgz -Igpgz .
+
+Likewise, the command below will list its contents:
-Likewise, the following command will list its contents:
+ $ tar -tf foo.tar.gpgz -Igpgz .
- $ tar -tf foo.tar.gpgz --use-compress=gpgz .
+* Menu:
+
+* lbzip2:: Using lbzip2 with GNU `tar'.
---------- Footnotes ----------
(1) It also had patent problems in the past.
+ (2) To verbosely trace the decompressor selection, use the
+`--warning=decompress-program' option (*note decompress-program:
+warnings.).
+
+\1f
+File: tar.info, Node: lbzip2, Up: gzip
+
+8.1.1.1 Using lbzip2 with GNU `tar'.
+....................................
+
+`Lbzip2' is a multithreaded utility for handling `bzip2' compression,
+written by Laszlo Ersek. It makes use of multiple processors to speed
+up its operation and in general works considerably faster than `bzip2'.
+For a detailed description of `lbzip2' see
+`http://freshmeat.net/projects/lbzip2' and lbzip2: parallel bzip2
+utility
+(http://www.linuxinsight.com/lbzip2-parallel-bzip2-utility.html).
+
+ Recent versions of `lbzip2' are mostly command line compatible with
+`bzip2', which makes it possible to automatically invoke it via the
+`--bzip2' GNU `tar' command line option. To do so, GNU `tar' must be
+configured with the `--with-bzip2' command line option, like this:
+
+ $ ./configure --with-bzip2=lbzip2 [OTHER-OPTIONS]
+
+ Once configured and compiled this way, `tar --help' will show the
+following:
+
+ $ tar --help | grep -- --bzip2
+ -j, --bzip2 filter the archive through lbzip2
+
+which means that running `tar --bzip2' will invoke `lbzip2'.
+
\1f
File: tar.info, Node: sparse, Prev: gzip, Up: Compression
8.2 Handling File Attributes
============================
- _(This message will disappear, once this node revised.)_
-
When `tar' reads files, it updates their access times. To avoid this,
use the `--atime-preserve[=METHOD]' option, which can either reset the
access time retroactively or avoid changing it in the first place.
- Handling of file attributes
-
`--atime-preserve'
`--atime-preserve=replace'
`--atime-preserve=system'
The numeric ids are _always_ saved into `tar' archives. The
identifying names are added at create time when provided by the
- system, unless `--old-archive' (`-o') is used. Numeric ids could
- be used when moving archives between a collection of machines using
- a centralized management for attribution of numeric ids to users
- and groups. This is often made through using the NIS capabilities.
+ system, unless `--format=oldgnu' is used. Numeric ids could be
+ used when moving archives between a collection of machines using a
+ centralized management for attribution of numeric ids to users and
+ groups. This is often made through using the NIS capabilities.
When making a `tar' file for distribution to other sites, it is
sometimes cleaner to use a single owner for all files in the
`--preserve'
Same as both `--same-permissions' and `--same-order'.
- The `--preserve' option has no equivalent short option name. It
- is equivalent to `--same-permissions' plus `--same-order'.
+ This option is deprecated, and will be removed in GNU `tar'
+ version 1.23.
\1f
Normally, when `tar' archives a symbolic link, it writes a block to the
archive naming the target of the link. In that way, the `tar' archive
-is a faithful record of the file system contents. `--dereference'
-(`-h') is used with `--create' (`-c'), and causes `tar' to archive the
-files symbolic links point to, instead of the links themselves. When
-this option is used, when `tar' encounters a symbolic link, it will
-archive the linked-to file, instead of simply recording the presence of
-a symbolic link.
-
- The name under which the file is stored in the file system is not
-recorded in the archive. To record both the symbolic link name and the
-file name in the system, archive the file under both names. If all
-links were recorded automatically by `tar', an extracted file might be
-linked to a file name that no longer exists in the file system.
-
- If a linked-to file is encountered again by `tar' while creating the
-same archive, an entire second copy of it will be stored. (This
-_might_ be considered a bug.)
-
- So, for portable archives, do not archive symbolic links as such,
-and use `--dereference' (`-h'): many systems do not support symbolic
-links, and moreover, your distribution might be unusable if it contains
-unresolved symbolic links.
+is a faithful record of the file system contents. When `--dereference'
+(`-h') is used with `--create' (`-c'), `tar' archives the files
+symbolic links point to, instead of the links themselves.
+
+ When creating portable archives, use `--dereference' (`-h'): some
+systems do not support symbolic links, and moreover, your distribution
+might be unusable if it contains unresolved symbolic links.
+
+ When reading from an archive, the `--dereference' (`-h') option
+causes `tar' to follow an already-existing symbolic link when `tar'
+writes or reads a file named in the archive. Ordinarily, `tar' does
+not follow such a link, though it may remove the link before writing a
+new file. *Note Dealing with Old Files::.
+
+ The `--dereference' option is unsafe if an untrusted user can modify
+directories while `tar' is running. *Note Security::.
\1f
File: tar.info, Node: hard links, Next: old, Prev: dereference, Up: Portability
8.3.3 Hard Links
----------------
- _(This message will disappear, once this node revised.)_
-
Normally, when `tar' archives a hard link, it writes a block to the
archive naming the target of the link (a `1' type block). In that way,
the actual file contents is stored in file only once. For example,
consider the following two files:
- $ ls
- -rw-r--r-- 2 gray staff 4 2007-10-30 15:11 one
- -rw-r--r-- 2 gray staff 4 2007-10-30 15:11 jeden
+ $ ls -l
+ -rw-r--r-- 2 gray staff 4 2007-10-30 15:11 one
+ -rw-r--r-- 2 gray staff 4 2007-10-30 15:11 jeden
Here, `jeden' is a link to `one'. When archiving this directory
with a verbose level 2, you will get an output similar to the following:
- $ tar cfvv ../archive.tar .
+ $ tar cvvf ../archive.tar .
drwxr-xr-x gray/staff 0 2007-10-30 15:13 ./
-rw-r--r-- gray/staff 4 2007-10-30 15:11 ./jeden
hrw-r--r-- gray/staff 0 2007-10-30 15:11 ./one link to ./jeden
For example, trying to archive only file `jeden' with this option
produces the following diagnostics:
- $ tar -c -f ../archive.tar jeden
- tar: Missing links to `jeden'.
+ $ tar -c -f ../archive.tar -l jeden
+ tar: Missing links to 'jeden'.
Although creating special records for hard links helps keep a
faithful record of the file system contents and makes archives more
of file `jeden':
$ tar xf archive.tar ./one
- tar: ./one: Cannot hard link to `./jeden': No such file or directory
+ tar: ./one: Cannot hard link to './jeden': No such file or directory
tar: Error exit delayed from previous errors
The reason for this behavior is that `tar' cannot seek back in the
Archive format defined by POSIX.1-1988 specification is called `ustar'.
Although it is more flexible than the V7 format, it still has many
-restrictions (*Note ustar: Formats, for the detailed description of
+restrictions (*note ustar: Formats, for the detailed description of
`ustar' format). Along with V7 format, `ustar' format is a good choice
for archives intended to be read with other implementations of `tar'.
%d/PaxHeaders.%p/%f
+`exthdr.mtime=VALUE'
+ This keyword defines the value of the `mtime' field that is
+ written into the ustar header blocks for the extended headers. By
+ default, the `mtime' field is set to the modification time of the
+ archive member described by that extended headers.
+
`globexthdr.name=STRING'
This keyword allows user control over the name that is written into
the ustar header blocks for global extended header records. The
where `$TMPDIR' represents the value of the TMPDIR environment
variable. If TMPDIR is not set, `tar' uses `/tmp'.
+`globexthdr.mtime=VALUE'
+ This keyword defines the value of the `mtime' field that is
+ written into the ustar header blocks for the global extended
+ headers. By default, the `mtime' field is set to the time when
+ `tar' was invoked.
+
`KEYWORD=VALUE'
When used with one of archive-creation commands, these
keyword/value pairs will be included at the beginning of the
the group name will be forced to a new value for all files stored
in the archive.
+ In any of the forms described above, the VALUE may be a string
+enclosed in curly braces. In that case, the string between the braces
+is understood either as a textual time representation, as described in
+*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.
+
+ For example, to set all modification times to the current date, you
+use the following option:
+
+ --pax-option='mtime:={now}'
+
+ Note quoting of the option's argument.
+
+ As another example, here is the option that ensures that any two
+archives created using it, will be binary equivalent if they have the
+same contents:
+
+ --pax-option=exthdr.name=%d/PaxHeaders/%f,atime:=0
+
\1f
File: tar.info, Node: Checksumming, Next: Large or Negative Values, Prev: posix, Up: Portability
characters with the eight bit set, because they use signed checksums,
while GNU `tar' uses unsigned checksums while creating archives, as per
POSIX standards. On reading, GNU `tar' computes both checksums and
-accept any. It is somewhat worrying that a lot of people may go around
-doing backup of their files using faulty (or at least non-standard)
-software, not learning about it until it's time to restore their
-missing files with an incompatible file extractor, or vice versa.
+accepts any. It is somewhat worrying that a lot of people may go
+around doing backup of their files using faulty (or at least
+non-standard) software, not learning about it until it's time to
+restore their missing files with an incompatible file extractor, or
+vice versa.
- GNU `tar' compute checksums both ways, and accept any on read, so
+ GNU `tar' computes checksums both ways, and accept any on read, so
GNU tar can read Sun tapes even with their wrong checksums. GNU `tar'
produces the standard checksum, however, raising incompatibilities with
Sun. That is to say, GNU `tar' has not been modified to _produce_
$ xsparse -n /home/gray/GNUSparseFile.6058/sparsefile
Reading v.1.0 sparse map
- Expanding file `/home/gray/GNUSparseFile.6058/sparsefile' to
- `/home/gray/sparsefile'
+ Expanding file '/home/gray/GNUSparseFile.6058/sparsefile' to
+ '/home/gray/sparsefile'
Finished dry run
To actually expand the file, you would run:
$ xsparse -v /home/gray/GNUSparseFile.6058/sparsefile
Reading v.1.0 sparse map
- Expanding file `/home/gray/GNUSparseFile.6058/sparsefile' to
- `/home/gray/sparsefile'
+ Expanding file '/home/gray/GNUSparseFile.6058/sparsefile' to
+ '/home/gray/sparsefile'
Done
Additionally, if your `tar' implementation has extracted the
Found variable GNU.sparse.name = sparsefile
Found variable GNU.sparse.realsize = 217481216
Reading v.1.0 sparse map
- Expanding file `/home/gray/GNUSparseFile.6058/sparsefile' to
- `/home/gray/sparsefile'
+ Expanding file '/home/gray/GNUSparseFile.6058/sparsefile' to
+ '/home/gray/sparsefile'
Done
An "extended header" is a special `tar' archive header that precedes
Found variable GNU.sparse.numblocks = 208
Found variable GNU.sparse.name = sparsefile
Found variable GNU.sparse.map = 0,2048,1050624,2048,...
- Expanding file `GNUSparseFile.28124/sparsefile' to `sparsefile'
+ Expanding file 'GNUSparseFile.28124/sparsefile' to 'sparsefile'
Done
---------- Footnotes ----------
(1) *Note PAX 1::.
- (2) technically speaking, N is a "process ID" of the `tar' process
+ (2) Technically speaking, N is a "process ID" of the `tar' process
which created the archive (*note PAX keywords::).
\1f
later).
`tar''s way of handling multiple hard links to a file can handle
-file systems that support 32-bit inumbers (e.g., the BSD file system);
+file systems that support 32-bit i-numbers (e.g., the BSD file system);
`cpio's way requires you to play some games (in its "binary" format,
i-numbers are only 16 bits, and in its "portable ASCII" format, they're
18 bits--it would have to play games with the "file system ID" field of
longer read it).
\1f
-File: tar.info, Node: Media, Next: Changes, Prev: Formats, Up: Top
+File: tar.info, Node: Media, Next: Reliability and security, Prev: Formats, Up: Top
9 Tapes and Other Archive Media
*******************************
sources for `tar'; it's compiled and installed by default. The exact
path to this utility is determined when configuring the package. It is
`PREFIX/libexec/rmt', where PREFIX stands for your installation prefix.
-This location may also be overridden at runtime by using
-`rmt-command=COMMAND' option (*Note --rmt-command: Option Summary, for
-detailed description of this option. *Note Remote Tape Server::, for
-the description of `rmt' command).
+This location may also be overridden at runtime by using the
+`--rmt-command=COMMAND' option (*Note --rmt-command: Option Summary,
+for detailed description of this option. *Note Remote Tape Server::,
+for the description of `rmt' command).
If this option is not given, but the environment variable `TAPE' is
set, its value is used; otherwise, old versions of `tar' used a default
*Note Multi-Volume Archives::.
`-L NUM'
-`--tape-length=NUM'
- Change tape after writing NUM x 1024 bytes.
-
- This option might be useful when your tape drivers do not properly
- detect end of physical tapes. By being slightly conservative on
- the maximum tape length, you might avoid the problem entirely.
+`--tape-length=SIZE[SUF]'
+ Change tape after writing SIZE units of data. Unless SUF is
+ given, SIZE is treated as kilobytes, i.e. `SIZE x 1024' bytes.
+ The following suffixes alter this behavior:
-`-F FILE'
-`--info-script=FILE'
-`--new-volume-script=FILE'
- Execute `file' at end of each tape. This implies `--multi-volume'
- (`-M'). *Note info-script::, for a detailed description of this
- option.
+ Suffix Units Byte Equivalent
+ --------------------------------------------------------
+ b Blocks SIZE x 512
+ B Kilobytes SIZE x 1024
+ c Bytes SIZE
+ G Gigabytes SIZE x 1024^3
+ K Kilobytes SIZE x 1024
+ k Kilobytes SIZE x 1024
+ M Megabytes SIZE x 1024^2
+ P Petabytes SIZE x 1024^5
+ T Terabytes SIZE x 1024^4
+ w Words SIZE x 2
+
+ Table 9.1: Size Suffixes
+
+ This option might be useful when your tape drivers do not
+ properly detect end of physical tapes. By being slightly
+ conservative on the maximum tape length, you might avoid the
+ problem entirely.
+
+ `-F COMMAND'
+ `--info-script=COMMAND'
+ `--new-volume-script=COMMAND'
+ Execute COMMAND at end of each tape. This implies
+ `--multi-volume' (`-M'). *Note info-script::, for a detailed
+ description of this option.
\1f
File: tar.info, Node: Remote Tape Server, Next: Common Problems and Solutions, Prev: Device, Up: Media
-9.2 The Remote Tape Server
-==========================
+9.2 Remote Tape Server
+======================
In order to access the tape drive on a remote machine, `tar' uses the
remote tape server written at the University of California at Berkeley.
an `rsh' or `remsh' to the remote machine, optionally using a different
login name if one is supplied.
- A copy of the source for the remote tape server is provided. It is
-Copyright (C) 1983 by the Regents of the University of California, but
-can be freely distributed. It is compiled and installed by default.
+ A copy of the source for the remote tape server is provided. Its
+source code can be freely distributed. It is compiled and installed by
+default.
Unless you use the `--absolute-names' (`-P') option, GNU `tar' will
not allow you to create an archive that contains absolute file names (a
written). This is currently possible only on two kinds of files: normal
disk files (or any other file that can be backspaced with `lseek'), and
industry-standard 9-track magnetic tape (or any other kind of tape that
-can be backspaced with the `MTIOCTOP' `ioctl'.
+can be backspaced with the `MTIOCTOP' `ioctl').
This means that the `--append', `--concatenate', and `--delete'
commands will not work on any other kind of file. Some media simply
9.4 Blocking
============
- _(This message will disappear, once this node revised.)_
-
"Block" and "record" terminology is rather confused, and it is also
confusing to the expert reader. On the other hand, readers who are new
to the field have a fresh mind, and they may safely skip the next two
When reading an archive, `tar' can usually figure out the record
size on itself. When this is the case, and a non-standard record size
was used when the archive was created, `tar' will print a message about
-a non-standard blocking factor, and then operate normally. On some
+a non-standard blocking factor, and then operate normally(1). On some
tape devices, however, `tar' cannot figure out the record size itself.
On most of those, you can specify a blocking factor (with
`--blocking-factor') larger than the actual blocking factor, and then
* Format Variations:: Format Variations
* Blocking Factor:: The Blocking Factor of an Archive
+ ---------- Footnotes ----------
+
+ (1) If this message is not needed, you can turn it off using the
+`--warning=no-record-size' option.
+
\1f
File: tar.info, Node: Format Variations, Next: Blocking Factor, Up: Blocking
sure what the blocking factor is), you can usually use the
`--read-full-records' (`-B') option while specifying a blocking factor
larger then the blocking factor of the archive (i.e., `tar --extract
---read-full-records --blocking-factor=300'. *Note list::, for more
+--read-full-records --blocking-factor=300'). *Note list::, for more
information on the `--list' (`-t') operation. *Note Reading::, for a
more detailed explanation of that option.
`-b BLOCKS'
`--blocking-factor=BLOCKS'
- Set record size to BLOCKS * 512 bytes.
+ Set record size to BLOCKS*512 bytes.
This option is used to specify a "blocking factor" for the archive.
When reading or writing the archive, `tar', will do reads and
for later regaining the reading or writing speed. When the tape driver
starts reading a record, the record has to be read whole without
stopping, as a tape gap is needed to stop the tape motion without
-loosing information.
+losing information.
Using higher blocking (putting more disk blocks per tape block) will
use the tape more efficiently as there will be less tape gaps. But
Moves tape position back NUMBER files.
`rewind'
- Rewinds the tape. (Ignores NUMBER).
+ Rewinds the tape. (Ignores NUMBER.)
`offline'
`rewoff1'
Rewinds the tape and takes the tape device off-line. (Ignores
- NUMBER).
+ NUMBER.)
`status'
Prints status information about the tape unit.
the media, use the `--multi-volume' (`-M') option in conjunction with
the `--create' option (*note create::). A "multi-volume" archive can
be manipulated like any other archive (provided the `--multi-volume'
-option is specified), but is stored on more than one tape or disk.
+option is specified), but is stored on more than one tape or file.
When you specify `--multi-volume', `tar' does not report an error
when it comes to the end of an archive volume (when reading), or the
detect the end of the tape itself, you can use `--tape-length' option
to inform it about the capacity of the tape:
-`--tape-length=SIZE'
-`-L SIZE'
- Set maximum length of a volume. The SIZE argument should then be
- the usable size of the tape in units of 1024 bytes. This option
- selects `--multi-volume' automatically. For example:
+`--tape-length=SIZE[SUF]'
+`-L SIZE[SUF]'
+ Set maximum length of a volume. The SUF, if given, specifies
+ units in which SIZE is expressed, e.g. `2M' mean 2 megabytes
+ (*note Table 9.1: size-suffixes, for a list of allowed size
+ suffixes). Without SUF, units of 1024 bytes (kilobyte) are
+ assumed.
+
+ This option selects `--multi-volume' automatically. For example:
$ tar --create --tape-length=41943040 --file=/dev/tape FILES
+ or, which is equivalent:
+
+ $ tar --create --tape-length=4G --file=/dev/tape FILES
+
When GNU `tar' comes to the end of a storage media, it asks you to
change the volume. The built-in prompt for POSIX locale is(1):
- Prepare volume #N for `ARCHIVE' and hit return:
+ Prepare volume #N for 'ARCHIVE' and hit return:
where N is the ordinal number of the volume to be created and ARCHIVE
is archive file or device name.
responses:
`?'
- Request `tar' to explain possible responses
+ Request `tar' to explain possible responses.
`q'
Request `tar' to exit immediately.
volume, and instruct `tar' to use it instead of its normal prompting
procedure:
-`--info-script=SCRIPT-NAME'
-`--new-volume-script=SCRIPT-NAME'
-`-F SCRIPT-NAME'
- Specify the full name of the volume script to use. The script can
- be used to eject cassettes, or to broadcast messages such as
+`--info-script=COMMAND'
+`--new-volume-script=COMMAND'
+`-F COMMAND'
+ Specify the command to invoke when switching volumes. The COMMAND
+ can be used to eject cassettes, or to broadcast messages such as
`Someone please come change my tape' when performing unattended
backups.
- The SCRIPT-NAME is executed without any command line arguments. It
-inherits `tar''s shell environment. Additional data is passed to it
-via the following environment variables:
+ The COMMAND can contain additional options, if such are needed.
+*Note Running External Commands: external, for a detailed discussion of
+the way GNU `tar' runs external commands. It inherits `tar''s shell
+environment. Additional data is passed to it via the following
+environment variables:
`TAR_VERSION'
GNU `tar' version number.
The name of the archive `tar' is processing.
`TAR_BLOCKING_FACTOR'
- Current blocking factor (*note Blocking::.
+ Current blocking factor (*note Blocking::).
`TAR_VOLUME'
Ordinal number of the volume `tar' is about to start.
`TAR_SUBCOMMAND'
- A short option describing the operation `tar' is executing *Note
+ A short option describing the operation `tar' is executing. *Note
Operations::, for a complete list of subcommand options.
`TAR_FORMAT'
File descriptor which can be used to communicate the new volume
name to `tar'.
+ These variables can be used in the COMMAND itself, provided that
+they are properly quoted to prevent them from being expanded by the
+shell that invokes `tar'.
+
The volume script can instruct `tar' to use new archive name, by
writing in to file descriptor `$TAR_FD' (see below for an example).
etc., just do either of:
$ tar --create --multi-volume --file=/dev/tape0 --file=/dev/tape1 FILES
- $ tar cMff /dev/tape0 /dev/tape1 FILES
+ $ tar -cM -f /dev/tape0 -f /dev/tape1 FILES
The second method is to use the `n' response to the tape-change
prompt.
(as given by `--file' option) and VOL is the ordinal number of the
archive being created:
- #! /bin/sh
+ #! /bin/bash
+ # For this script it's advisable to use a shell, such as Bash,
+ # that supports a TAR_FD value greater than 9.
+
echo Preparing volume $TAR_VOLUME of $TAR_ARCHIVE.
name=`expr $TAR_ARCHIVE : '\(.*\)-.*'`
(1) If you run GNU `tar' under a different locale, the translation
to the locale's language will be used.
- (2) *Note --restrict::, for more information about this option
+ (2) *Note --restrict::, for more information about this option.
\1f
File: tar.info, Node: Tape Files, Next: Tarcat, Prev: Multi-Volume Archives, Up: Using Multiple Tapes
listed with `--list'. If you are creating a multi-volume archive with
`--multi-volume' (*note Using Multiple Tapes::), then the volume label
will have `Volume NNN' appended to the name you give, where NNN is the
-number of the volume of the archive. (If you use the
-`--label=VOLUME-LABEL') option when reading an archive, it checks to
-make sure the label on the tape matches the one you give. *Note label::.
+number of the volume of the archive. If you use the
+`--label=VOLUME-LABEL' option when reading an archive, it checks to
+make sure the label on the tape matches the one you gave. *Note
+label::.
When `tar' writes an archive to tape, it creates a single tape file.
If multiple archives are written to the same tape, one after the other,
9.7 Including a Label in the Archive
====================================
- _(This message will disappear, once this node revised.)_
-
To avoid problems caused by misplaced paper labels on the archive
-media, you can include a "label" entry--an archive member which
-contains the name of the archive--in the archive itself. Use the
-`--label=ARCHIVE-LABEL' (`-V ARCHIVE-LABEL') option in conjunction with
-the `--create' operation to include a label entry in the archive as it
-is being created.
+media, you can include a "label" entry -- an archive member which
+contains the name of the archive -- in the archive itself. Use the
+`--label=ARCHIVE-LABEL' (`-V ARCHIVE-LABEL') option(1) in conjunction
+with the `--create' operation to include a label entry in the archive
+as it is being created.
`--label=ARCHIVE-LABEL'
`-V ARCHIVE-LABEL'
the archive is being created, when used in conjunction with the
`--create' operation. Checks to make sure the archive label
matches the one specified (when used in conjunction with any other
- operation.
+ operation).
If you create an archive using both `--label=ARCHIVE-LABEL' (`-V
ARCHIVE-LABEL') and `--multi-volume' (`-M'), each volume of the archive
marked as in the example below:
$ tar --verbose --list --file=iamanarchive
- V--------- 0 0 0 1992-03-07 12:01 iamalabel--Volume Header--
- -rw-r--r-- ringo user 40 1990-05-21 13:30 iamafilename
+ V--------- 0/0 0 1992-03-07 12:01 iamalabel--Volume Header--
+ -rw-r--r-- ringo/user 40 1990-05-21 13:30 iamafilename
However, `--list' option will cause listing entire contents of the
archive, which may be undesirable (for example, if the archive is
-stored on a tape). You can request checking only the volume by
+stored on a tape). You can request checking only the volume label by
specifying `--test-label' option. This option reads only the first
block of an archive, so it can be used with slow storage devices. For
example:
$ tar --test-label --file=iamanarchive
iamalabel
- If `--test-label' is used with a single command line argument, `tar'
-compares the volume label with the argument. It exits with code 0 if
-the two strings match, and with code 2 otherwise. In this case no
-output is displayed. For example:
+ If `--test-label' is used with one or more command line arguments,
+`tar' compares the volume label with each argument. It exits with code
+0 if a match is found, and with code 1 otherwise(2). No output is
+displayed, unless you also used the `--verbose' option. For example:
- $ tar --test-label --file=iamanarchive 'iamalable'
+ $ tar --test-label --file=iamanarchive 'iamalabel'
=> 0
- $ tar --test-label --file=iamanarchive 'iamalable' alabel
+ $ tar --test-label --file=iamanarchive 'alabel'
+ => 1
+
+ When used with the `--verbose' option, `tar' prints the actual
+volume label (if any), and a verbose diagnostics in case of a mismatch:
+
+ $ tar --test-label --verbose --file=iamanarchive 'iamalabel'
+ iamalabel
+ => 0
+ $ tar --test-label --verbose --file=iamanarchive 'alabel'
+ iamalabel
+ tar: Archive label mismatch
=> 1
If you request any operation, other than `--create', along with
presumably labeled with string `My volume', you will get:
$ tar -rf archive --label 'My volume' .
- tar: Archive not labeled to match `My volume'
+ tar: Archive not labeled to match 'My volume'
in case its label does not match. This will work even if `archive' is
not labeled at all.
label doesn't match the ARCHIVE-LABEL specified. In those cases,
ARCHIVE-LABEL argument is interpreted as a globbing-style pattern which
must match the actual magnetic volume label. *Note exclude::, for a
-precise description of how match is attempted(1). If the switch
+precise description of how match is attempted(3). If the switch
`--multi-volume' (`-M') is being used, the volume label matcher will
also suffix ARCHIVE-LABEL by ` Volume [1-9]*' if the initial match
fails, before giving up. Since the volume numbering is automatically
added in labels at creation time, it sounded logical to equally help
the user taking care of it when the archive is being read.
- The `--label' was once called `--volume', but is not available under
-that name anymore.
-
You can also use `--label' to get a common information on all tapes
of a series. For having this information different in each series
created through a single script used on a regular basis, just manage to
get some date string as part of the label. For example:
- $ tar cfMV /dev/tape "Daily backup for `date +%Y-%m-%d`"
+ $ tar -cM -f /dev/tape -V "Daily backup for `date +%Y-%m-%d`"
$ tar --create --file=/dev/tape --multi-volume \
- --volume="Daily backup for `date +%Y-%m-%d`"
+ --label="Daily backup for `date +%Y-%m-%d`"
+
+ Some more notes about volume labels:
+
+ * Each label has its own date and time, which corresponds to the
+ time when GNU `tar' initially attempted to write it, often soon
+ after the operator launches `tar' or types the carriage return
+ telling that the next tape is ready.
- Also note that each label has its own date and time, which
-corresponds to when GNU `tar' initially attempted to write it, often
-soon after the operator launches `tar' or types the carriage return
-telling that the next tape is ready. Comparing date labels does give
-an idea of tape throughput only if the delays for rewinding tapes and
-the operator switching them were negligible, which is usually not the
-case.
+ * Comparing date labels to get an idea of tape throughput is
+ unreliable. It gives correct results only if the delays for
+ rewinding tapes and the operator switching them were negligible,
+ which is usually not the case.
---------- Footnotes ----------
- (1) Previous versions of `tar' used full regular expression
+ (1) Until version 1.10, that option was called `--volume', but is
+not available under that name anymore.
+
+ (2) Note that GNU `tar' versions up to 1.23 indicated mismatch with
+an exit code 2 and printed a spurious diagnostics on stderr.
+
+ (3) Previous versions of `tar' used full regular expression
matching, or before that, only exact string matching, instead of
wildcard matchers. We decided for the sake of simplicity to use a
uniform matching device through `tar'.
an archive is written, you should write protect the media to prevent
the archive from being accidentally overwritten or deleted. (This will
protect the archive from being changed with a tape or floppy drive--it
-will not protect it from magnet fields or other physical hazards).
+will not protect it from magnet fields or other physical hazards.)
The write protection device itself is usually an integral part of the
physical media, and can be a two position (write enabled/write
changeable feature.
\1f
-File: tar.info, Node: Changes, Next: Configuring Help Summary, Prev: Media, Up: Top
+File: tar.info, Node: Reliability and security, Next: Changes, Prev: Media, Up: Top
+
+10 Reliability and Security
+***************************
+
+The `tar' command reads and writes files as any other application does,
+and is subject to the usual caveats about reliability and security.
+This section contains some commonsense advice on the topic.
+
+* Menu:
+
+* Reliability::
+* Security::
+
+\1f
+File: tar.info, Node: Reliability, Next: Security, Up: Reliability and security
+
+10.1 Reliability
+================
+
+Ideally, when `tar' is creating an archive, it reads from a file system
+that is not being modified, and encounters no errors or inconsistencies
+while reading and writing. If this is the case, the archive should
+faithfully reflect what was read. Similarly, when extracting from an
+archive, ideally `tar' ideally encounters no errors and the extracted
+files faithfully reflect what was in the archive.
+
+ However, when reading or writing real-world file systems, several
+things can go wrong; these include permissions problems, corruption of
+data, and race conditions.
+
+* Menu:
+
+* Permissions problems::
+* Data corruption and repair::
+* Race conditions::
+
+\1f
+File: tar.info, Node: Permissions problems, Next: Data corruption and repair, Up: Reliability
+
+10.1.1 Permissions Problems
+---------------------------
+
+If `tar' encounters errors while reading or writing files, it normally
+reports an error and exits with nonzero status. The work it does may
+therefore be incomplete. For example, when creating an archive, if
+`tar' cannot read a file then it cannot copy the file into the archive.
+
+\1f
+File: tar.info, Node: Data corruption and repair, Next: Race conditions, Prev: Permissions problems, Up: Reliability
+
+10.1.2 Data Corruption and Repair
+---------------------------------
+
+If an archive becomes corrupted by an I/O error, this may corrupt the
+data in an extracted file. Worse, it may corrupt the file's metadata,
+which may cause later parts of the archive to become misinterpreted.
+An tar-format archive contains a checksum that most likely will detect
+errors in the metadata, but it will not detect errors in the data.
+
+ If data corruption is a concern, you can compute and check your own
+checksums of an archive by using other programs, such as `cksum'.
+
+ When attempting to recover from a read error or data corruption in an
+archive, you may need to skip past the questionable data and read the
+rest of the archive. This requires some expertise in the archive
+format and in other software tools.
+
+\1f
+File: tar.info, Node: Race conditions, Prev: Data corruption and repair, Up: Reliability
+
+10.1.3 Race conditions
+----------------------
+
+If some other process is modifying the file system while `tar' is
+reading or writing files, the result may well be inconsistent due to
+race conditions. For example, if another process creates some files in
+a directory while `tar' is creating an archive containing the
+directory's files, `tar' may see some of the files but not others, or
+it may see a file that is in the process of being created. The
+resulting archive may not be a snapshot of the file system at any point
+in time. If an application such as a database system depends on an
+accurate snapshot, restoring from the `tar' archive of a live file
+system may therefore break that consistency and may break the
+application. The simplest way to avoid the consistency issues is to
+avoid making other changes to the file system while tar is reading it
+or writing it.
+
+ When creating an archive, several options are available to avoid race
+conditions. Some hosts have a way of snapshotting a file system, or of
+temporarily suspending all changes to a file system, by (say)
+suspending the only virtual machine that can modify a file system; if
+you use these facilities and have `tar -c' read from a snapshot when
+creating an archive, you can avoid inconsistency problems. More
+drastically, before starting `tar' you could suspend or shut down all
+processes other than `tar' that have access to the file system, or you
+could unmount the file system and then mount it read-only.
+
+ When extracting from an archive, one approach to avoid race
+conditions is to create a directory that no other process can write to,
+and extract into that.
+
+\1f
+File: tar.info, Node: Security, Prev: Reliability, Up: Reliability and security
+
+10.2 Security
+=============
+
+In some cases `tar' may be used in an adversarial situation, where an
+untrusted user is attempting to gain information about or modify
+otherwise-inaccessible files. Dealing with untrusted data (that is,
+data generated by an untrusted user) typically requires extra care,
+because even the smallest mistake in the use of `tar' is more likely to
+be exploited by an adversary than by a race condition.
+
+* Menu:
+
+* Privacy::
+* Integrity::
+* Live untrusted data::
+* Security rules of thumb::
+
+\1f
+File: tar.info, Node: Privacy, Next: Integrity, Up: Security
+
+10.2.1 Privacy
+--------------
+
+Standard privacy concerns apply when using `tar'. For example, suppose
+you are archiving your home directory into a file
+`/archive/myhome.tar'. Any secret information in your home directory,
+such as your SSH secret keys, are copied faithfully into the archive.
+Therefore, if your home directory contains any file that should not be
+read by some other user, the archive itself should be not be readable
+by that user. And even if the archive's data are inaccessible to
+untrusted users, its metadata (such as size or last-modified date) may
+reveal some information about your home directory; if the metadata are
+intended to be private, the archive's parent directory should also be
+inaccessible to untrusted users.
+
+ One precaution is to create `/archive' so that it is not accessible
+to any user, unless that user also has permission to access all the
+files in your home directory.
+
+ Similarly, when extracting from an archive, take care that the
+permissions of the extracted files are not more generous than what you
+want. Even if the archive itself is readable only to you, files
+extracted from it have their own permissions that may differ.
+
+\1f
+File: tar.info, Node: Integrity, Next: Live untrusted data, Prev: Privacy, Up: Security
+
+10.2.2 Integrity
+----------------
+
+When creating archives, take care that they are not writable by a
+untrusted user; otherwise, that user could modify the archive, and when
+you later extract from the archive you will get incorrect data.
+
+ When `tar' extracts from an archive, by default it writes into files
+relative to the working directory. If the archive was generated by an
+untrusted user, that user therefore can write into any file under the
+working directory. If the working directory contains a symbolic link
+to another directory, the untrusted user can also write into any file
+under the referenced directory. When extracting from an untrusted
+archive, it is therefore good practice to create an empty directory and
+run `tar' in that directory.
+
+ When extracting from two or more untrusted archives, each one should
+be extracted independently, into different empty directories.
+Otherwise, the first archive could create a symbolic link into an area
+outside the working directory, and the second one could follow the link
+and overwrite data that is not under the working directory. For
+example, when restoring from a series of incremental dumps, the
+archives should have been created by a trusted process, as otherwise
+the incremental restores might alter data outside the working directory.
+
+ If you use the `--absolute-names' (`-P') option when extracting,
+`tar' respects any file names in the archive, even file names that
+begin with `/' or contain `..'. As this lets the archive overwrite any
+file in your system that you can write, the `--absolute-names' (`-P')
+option should be used only for trusted archives.
+
+ Conversely, with the `--keep-old-files' (`-k') and
+`--skip-old-files' options, `tar' refuses to replace existing files
+when extracting. The difference between the two options is that the
+former treats existing files as errors whereas the latter just silently
+ignores them.
+
+ Finally, with the `--no-overwrite-dir' option, `tar' refuses to
+replace the permissions or ownership of already-existing directories.
+These options may help when extracting from untrusted archives.
+
+\1f
+File: tar.info, Node: Live untrusted data, Next: Security rules of thumb, Prev: Integrity, Up: Security
+
+10.2.3 Dealing with Live Untrusted Data
+---------------------------------------
+
+Extra care is required when creating from or extracting into a file
+system that is accessible to untrusted users. For example, superusers
+who invoke `tar' must be wary about its actions being hijacked by an
+adversary who is reading or writing the file system at the same time
+that `tar' is operating.
+
+ When creating an archive from a live file system, `tar' is
+vulnerable to denial-of-service attacks. For example, an adversarial
+user could create the illusion of an indefinitely-deep directory
+hierarchy `d/e/f/g/...' by creating directories one step ahead of
+`tar', or the illusion of an indefinitely-long file by creating a
+sparse file but arranging for blocks to be allocated just before `tar'
+reads them. There is no easy way for `tar' to distinguish these
+scenarios from legitimate uses, so you may need to monitor `tar', just
+as you'd need to monitor any other system service, to detect such
+attacks.
+
+ While a superuser is extracting from an archive into a live file
+system, an untrusted user might replace a directory with a symbolic
+link, in hopes that `tar' will follow the symbolic link and extract
+data into files that the untrusted user does not have access to. Even
+if the archive was generated by the superuser, it may contain a file
+such as `d/etc/passwd' that the untrusted user earlier created in order
+to break in; if the untrusted user replaces the directory `d/etc' with
+a symbolic link to `/etc' while `tar' is running, `tar' will overwrite
+`/etc/passwd'. This attack can be prevented by extracting into a
+directory that is inaccessible to untrusted users.
+
+ Similar attacks via symbolic links are also possible when creating an
+archive, if the untrusted user can modify an ancestor of a top-level
+argument of `tar'. For example, an untrusted user that can modify
+`/home/eve' can hijack a running instance of `tar -cf -
+/home/eve/Documents/yesterday' by replacing `/home/eve/Documents' with
+a symbolic link to some other location. Attacks like these can be
+prevented by making sure that untrusted users cannot modify any files
+that are top-level arguments to `tar', or any ancestor directories of
+these files.
+
+\1f
+File: tar.info, Node: Security rules of thumb, Prev: Live untrusted data, Up: Security
+
+10.2.4 Security Rules of Thumb
+------------------------------
+
+This section briefly summarizes rules of thumb for avoiding security
+pitfalls.
+
+ * Protect archives at least as much as you protect any of the files
+ being archived.
+
+ * Extract from an untrusted archive only into an otherwise-empty
+ directory. This directory and its parent should be accessible
+ only to trusted users. For example:
+
+ $ chmod go-rwx .
+ $ mkdir -m go-rwx dir
+ $ cd dir
+ $ tar -xvf /archives/got-it-off-the-net.tar.gz
+
+ As a corollary, do not do an incremental restore from an untrusted
+ archive.
+
+ * Do not let untrusted users access files extracted from untrusted
+ archives without checking first for problems such as setuid
+ programs.
+
+ * Do not let untrusted users modify directories that are ancestors of
+ top-level arguments of `tar'. For example, while you are
+ executing `tar -cf /archive/u-home.tar /u/home', do not let an
+ untrusted user modify `/', `/archive', or `/u'.
+
+ * Pay attention to the diagnostics and exit status of `tar'.
+
+ * When archiving live file systems, monitor running instances of
+ `tar' to detect denial-of-service attacks.
+
+ * Avoid unusual options such as `--absolute-names' (`-P'),
+ `--dereference' (`-h'), `--overwrite', `--recursive-unlink', and
+ `--remove-files' unless you understand their security implications.
+
+
+\1f
+File: tar.info, Node: Changes, Next: Configuring Help Summary, Prev: Reliability and security, Up: Top
Appendix A Changes
******************
This appendix lists some important user-visible changes between version
-GNU `tar' 1.21 and previous versions. An up-to-date version of this
+GNU `tar' 1.27 and previous versions. An up-to-date version of this
document is available at the GNU `tar' documentation page
(http://www.gnu.org/software/tar/manual/changes.html).
tar: *.c: Not found in archive
tar: Error exit delayed from previous errors
- To treat member names as globbing patterns, use -wildcards option.
- If you want to tar to mimic the behavior of versions prior to
- 1.15.91, add this option to your `TAR_OPTIONS' variable.
+ To treat member names as globbing patterns, use the `--wildcards'
+ option. If you want to tar to mimic the behavior of versions
+ prior to 1.15.91, add this option to your `TAR_OPTIONS' variable.
*Note wildcards::, for the detailed discussion of the use of
globbing patterns by GNU `tar'.
distribution tarballs. *Note v7: Formats, for the detailed
discussion of this issue and its implications.
- . *Note tar-v7: (automake)Options, for a description on how to
+ *Note tar-formats: (automake)Options, for a description on how to
use various archive formats with `automake'.
Future versions of GNU `tar' will understand `-o' only as a
Use of short option `-l'
Earlier versions of GNU `tar' understood `-l' option as a synonym
for `--one-file-system'. Since such usage contradicted to UNIX98
- specification and harmed compatibility with other implementation,
+ specification and harmed compatibility with other implementations,
it was declared deprecated in version 1.14. However, to
facilitate transition to its new semantics, it was supported by
versions 1.15 and 1.15.90. The present use of `-l' as a short
Appendix C Fixing Snapshot Files
********************************
-Sometimes device numbers can change after upgrading your kernel version
-or recofiguring the harvare. Reportedly this is the case with some
-newer Linux kernels, when using LVM. In majority of cases this change
-is unnoticed by the users. However, it influences `tar' incremental
+Various situations can cause device numbers to change: upgrading your
+kernel version, reconfiguring your hardware, loading kernel modules in a
+different order, using virtual volumes that are assembled dynamically
+(such as with LVM or RAID), hot-plugging drives (e.g. external USB or
+Firewire drives), etc. In the majority of cases this change is
+unnoticed by the users. However, it influences `tar' incremental
backups: the device number is stored in tar snapshot files (*note
Snapshot Files::) and is used to determine whether the file has changed
since the last backup. If the device numbers change for some reason,
-the next backup you run will be a full backup.
+by default the next backup you run will be a full backup.
To minimize the impact in these cases, GNU `tar' comes with the
`tar-snapshot-edit' utility for inspecting and updating device numbers
-in snapshot files. The utility, written by Dustin J. Mitchell, is
-available from GNU `tar' home page
-(http://www.gnu.org/software/tar/utils/tar-snapshot-edit.html).
+in snapshot files. (The utility, written by Dustin J. Mitchell, is
+also available from the GNU `tar' home page
+(http://www.gnu.org/software/tar/utils/tar-snapshot-edit.html).)
- To obtain the device numbers used in the snapshot file, run
+ To obtain a summary of the device numbers found in the snapshot
+file, run
$ tar-snapshot-edit SNAPFILE
where SNAPFILE is the name of the snapshot file (you can supply as many
-files as you wish in a single command line ).
-
- To update all occurrences of the given device number in the file, use
-`-r' option. It takes a single argument of the form `OLDDEV-NEWDEV',
-where OLDDEV is the device number used in the snapshot file, and NEWDEV
-is the corresponding new device number. Both numbers may be specified
-in hex (e.g., `0xfe01'), decimal (e.g., `65025'), or as a major:minor
-number pair (e.g., `254:1'). To change several device numbers at once,
-specify them in a single comma-separated list, as in `-r
-0x3060-0x4500,0x307-0x4600'.
+files as you wish in a single command line). You can then compare the
+numbers across snapshot files, or against those currently in use on the
+live filesystem (using `ls -l' or `stat').
+
+ Assuming the device numbers have indeed changed, it's often possible
+to simply tell GNU `tar' to ignore the device number when processing the
+incremental snapshot files for these backups, using the
+`--no-check-device' option (*note device numbers::).
+
+ Alternatively, you can use the `tar-edit-snapshot' script's `-r'
+option to update all occurrences of the given device number in the
+snapshot file(s). It takes a single argument of the form
+`OLDDEV-NEWDEV', where OLDDEV is the device number used in the
+snapshot file, and NEWDEV is the corresponding new device number. Both
+numbers may be specified in hex (e.g., `0xfe01'), decimal (e.g.,
+`65025'), or as a major:minor number pair (e.g., `254:1'). To change
+several device numbers at once, specify them in a single
+comma-separated list, as in `-r 0x3060-0x4500,0x307-0x4600'.
Before updating the snapshot file, it is a good idea to create a
backup copy of it. This is accomplished by `-b' option. The name of
the backup file is obtained by appending `~' to the original file name.
An example session:
- $ tar-snapshot-edit /var/backup/snap.a
- file version 2
- /tmp/snap: Device 0x0306 occurs 634 times.
- $ tar-snapshot-edit -b -r 0x0306-0x4500 /var/backup/snap.a
- file version 2
+ $ tar-snapshot-edit root_snap.0 boot_snap.0
+ File: root_snap.0
+ Detected snapshot file version: 2
+
+ Device 0x0000 occurs 1 times.
+ Device 0x0003 occurs 1 times.
+ Device 0x0005 occurs 1 times.
+ Device 0x0013 occurs 1 times.
+ Device 0x6801 occurs 1 times.
+ Device 0x6803 occurs 6626 times.
+ Device 0xfb00 occurs 1 times.
+
+ File: boot_snap.0
+ Detected snapshot file version: 2
+
+ Device 0x6801 occurs 3 times.
+ $ tar-snapshot-edit -b -r 0x6801-0x6901,0x6803-0x6903 root_snap.0 boot_snap.0
+ File: root_snap.0
+ Detected snapshot file version: 2
+
+ Updated 6627 records.
+
+ File: boot_snap.0
+ Detected snapshot file version: 2
+
+ Updated 3 records.
\1f
File: tar.info, Node: Tar Internals, Next: Genfile, Prev: Fixing Snapshot Files, Up: Top
/* tar Header Block, GNU extensions. */
/* In GNU tar, SYMTYPE is for to symbolic links, and CONTTYPE is for
- contiguous files, so maybe disobeying the `reserved' comment in POSIX
+ contiguous files, so maybe disobeying the "reserved" comment in POSIX
header description. I suspect these were meant to be used this way, and
- should not have really been `reserved' in the published standards. */
+ should not have really been "reserved" in the published standards. */
/* *BEWARE* *BEWARE* *BEWARE* that the following information is still
boiling, and may change. Even if the OLDGNU format description should be
contained many flaws, it was the only format GNU `tar' supported until
version 1.14 (May, 2004), which introduced initial support for sparse
archives in PAX archives (*note posix::). This format was not free
-from design flows, either and it was subsequently improved in versions
+from design flaws, either and it was subsequently improved in versions
1.15.2 (November, 2005) and 1.15.92 (June, 2006).
In addition to GNU sparse format, GNU `tar' is able to read and
D.0.1 Old GNU Format
--------------------
-The format introduced some time around 1990 (v. 1.09). It was designed
-on top of standard `ustar' headers in such an unfortunate way that some
-of its fields overwrote fields required by POSIX.
+The format introduced in November 1990 (v. 1.09) was designed on top of
+standard `ustar' headers in such an unfortunate way that some of its
+fields overwrote fields required by POSIX.
An old GNU sparse header is designated by type `S'
(`GNUTYPE_SPARSE') and has the following layout:
Offset Size Name Data type Contents
----------------------------------------------------------------------------
-0 21 sp `sparse_header' (21 entires) File map.
+0 21 sp `sparse_header' (21 entries) File map.
504 1 isextended Bool `1' if an extension sparse
header follows, or `0'
otherwise.
variables:
`GNU.sparse.size'
- Real size of the stored file
+ Real size of the stored file;
`GNU.sparse.numblocks'
- Number of blocks in the sparse map
+ Number of blocks in the sparse map;
`GNU.sparse.offset'
- Offset of the data block
+ Offset of the data block;
`GNU.sparse.numbytes'
- Size of the data block
+ Size of the data block.
The latter two variables repeat for each data block, so the overall
structure is like this:
`GNU.sparse.offset' and `GNU.sparse.numbytes' are conflicting with
the POSIX specs.
- 2. Attempting to extract such archives using a third-party `tar's
- results in extraction of sparse files in _compressed form_. If
- the `tar' implementation in question does not support POSIX
- format, it will also extract a file containing extension header
- attributes. This file can be used to expand the file to its
- original state. However, posix-aware `tar's will usually ignore
- the unknown variables, which makes restoring the file more
- difficult. *Note Extraction of sparse members in v.0.0 format:
- extracting sparse v.0.x, for the detailed description of how to
- restore such members using non-GNU `tar's.
+ 2. Attempting to extract such archives using a third-party's `tar'
+ results in extraction of sparse files in _condensed form_. If the
+ `tar' implementation in question does not support POSIX format, it
+ will also extract a file containing extension header attributes.
+ This file can be used to expand the file to its original state.
+ However, posix-aware `tar's will usually ignore the unknown
+ variables, which makes restoring the file more difficult. *Note
+ Extraction of sparse members in v.0.0 format: extracting sparse
+ v.0.x, for the detailed description of how to restore such members
+ using non-GNU `tar's.
GNU `tar' 1.15.2 introduced sparse format version `0.1', which
attempted to solve these problems. As its predecessor, this format
The resulting `GNU.sparse.map' string can be _very_ long. Although
POSIX does not impose any limit on the length of a `x' header variable,
-this possibly can confuse some tars.
+this possibly can confuse some `tar's.
\1f
File: tar.info, Node: PAX 1, Prev: PAX 0, Up: Sparse Formats
are map entries, each one consisting of two numbers giving the offset
and size of the data block it describes.
- The format is designed in such a way that non-posix aware tars and
-tars not supporting `GNU.sparse.*' keywords will extract each sparse
+ The format is designed in such a way that non-posix aware `tar's and
+`tar's not supporting `GNU.sparse.*' keywords will extract each sparse
file in its condensed form with the file map prepended and will place it
into a separate directory. Then, using a simple program it would be
possible to expand the file to its original form even without GNU `tar'.
file system at the time of the dump and is used to determine which
files were modified since the last backup.
- GNU `tar' version 1.21 supports three snapshot file formats. The
+ GNU `tar' version 1.27 supports three snapshot file formats. The
first format, called "format 0", is the one used by GNU `tar' versions
-up to 1.15.1. The second format, called "format 1" is an extended
-version of this format, that contains more metadata and allows for
-further extensions. It was used by version 1.15.1. Starting from
-version 1.16 and up to 1.21, the "format 2" is used.
+up to and including 1.15.1. The second format, called "format 1" is an
+extended version of this format, that contains more metadata and allows
+for further extensions. It was used by alpha release version 1.15.90.
+For alpha version 1.15.91 and stable releases version 1.16 up through
+1.27, the "format 2" is used.
GNU `tar' is able to read all three formats, but will create
snapshots only in format 2.
descriptions, one per line. Each description has the following
format:
- NFSDEV INODE NAME
+ [NFS]DEV INODE NAME
where:
NFS
A single plus character (`+'), if this directory is located on
- an NFS-mounted partition, or a single space otherwise;
+ an NFS-mounted partition, otherwise empty.
+
+ (That is, for non-NFS directories, the first character on the
+ description line contains the start of the DEV field.)
DEV
Device number of the directory;
this directory with nanosecond precision; NFS, DEV, INODE and NAME
have the same meaning as with `format 0'.
- 2. A snapshot file begins with a format identifier, as described
- for version 1, e.g.:
+ 2. `Format 2' snapshot file begins with a format identifier, as
+ described for version 1, e.g.:
- GNU tar-1.21-2
+ GNU tar-1.27-2
This line is followed by newline. Rest of file consists of
records, separated by null (ASCII 0) characters. Thus, in contrast
to the previous formats, format 2 snapshot is a binary file.
- First two records are decimal numbers, representing the time of
+ First two records are decimal integers, representing the time of
the last backup. First number is the number of seconds, the
second one is the number of nanoseconds, since the beginning of the
epoch. These are followed by arbitrary number of directory
Each "directory record" contains a set of metadata describing a
particular directory. Parts of a directory record are delimited
with ASCII 0 characters. The following table describes each part.
- The "Number" type in this table stands for a decimal number in
- ASCII notation.
-
- Field Type Description
- ---------------------------------------------------------------------
- nfs Character `1' if the directory is located on an
- NFS-mounted partition, or `0' otherwise;
- mtime-sec Number Modification time, seconds;
- mtime-nano Number Modification time, nanoseconds;
- dev-no Number Device number;
- i-no Number I-node number;
- name String Directory name; In contrast to the
- previous versions it is not quoted.
- contents Dumpdir Contents of the directory; *Note
- Dumpdir::, for a description of its
- format.
+ The "Number" type in this table stands for a decimal integer in
+ ASCII notation. (Negative values are preceeded with a "-"
+ character, while positive values have no leading punctuation.)
+
+ Field Type Description
+ ----------------------------------------------------------------------
+ nfs Character `1' if the directory is located on an
+ NFS-mounted partition, or `0' otherwise;
+ timestamp_sec Number Modification time, seconds;
+ timestamp_nsec Number Modification time, nanoseconds;
+ dev Number Device number;
+ ino Number I-node number;
+ name String Directory name; in contrast to the
+ previous versions it is not quoted;
+ contents Dumpdir Contents of the directory; *Note
+ Dumpdir::, for a description of its
+ format.
Dumpdirs stored in snapshot files contain only records of types
`Y', `N' and `D'.
+ The specific range of values allowed in each of the "Number" fields
+ depends on the underlying C datatypes as determined when `tar' is
+ compiled. To see the specific ranges allowed for a particular
+ `tar' binary, you can use the `--show-snapshot-field-ranges'
+ option:
+
+ $ tar --show-shapshot-field-ranges
+ This tar's snapshot file field ranges are
+ (field name => [ min, max ]):
+
+ nfs => [ 0, 1 ],
+ timestamp_sec => [ -9223372036854775808, 9223372036854775807 ],
+ timestamp_nsec => [ 0, 999999999 ],
+ dev => [ 0, 18446744073709551615 ],
+ ino => [ 0, 18446744073709551615 ],
+
+ (This example is from a GNU/Linux x86_64 system.)
+
\1f
File: tar.info, Node: Dumpdir, Prev: Snapshot Files, Up: Tar Internals
specified in the command line. This mode is toggled by `--stat' (`-S')
command line option. An optional argument to this option specifies
output "format": a comma-separated list of `struct stat' fields to be
-displayed. This list can contain following identifiers :
+displayed. This list can contain following identifiers:
name
The file name.
mode.
The `Exec Mode' is toggled by `--run' command line option (or its
-alias `-r'). The argument to this option gives the command line to be
-executed. The actual command line is constructed by inserting
-`--checkpoint' option between the command name and its first argument
-(if any). Due to this, the argument to `--run' may not use traditional
-`tar' option syntax, i.e., the following is wrong:
-
- # Wrong!
- genfile --run 'tar cf foo bar'
-
-Use the following syntax instead:
-
- genfile --run 'tar -cf foo bar'
+alias `-r'). The non-optional arguments to `getopt' give the command
+line to be executed. Normally, it should contain at least the
+`--checkpoint' option.
- The rest of command line after `--run' or its equivalent specifies
-checkpoint values and actions to be executed upon reaching them.
-Checkpoint values are introduced with `--checkpoint' command line
-option. Argument to this option is the number of checkpoint in decimal.
+ A set of options is provided for defining checkpoint values and
+actions to be executed upon reaching them. Checkpoint values are
+introduced with the `--checkpoint' command line option. Argument to
+this option is the number of checkpoint in decimal.
Any number of "actions" may be specified after a checkpoint.
Available actions are
`--exec COMMAND'
Execute given shell command.
+`--unlink FILE'
+ Unlink the FILE.
Option `--verbose' instructs `genfile' to print on standard output
notifications about checkpoints being executed and to verbosely
`Genfile' exits with the exit status of the executed command.
+ For compatibility with previous `genfile' versions, the `--run'
+option takes an optional argument. If used this way, its argument
+supplies the command line to be executed. There should be no
+non-optional arguments in the `genfile' command line.
+
+ The actual command line is constructed by inserting the
+`--checkpoint' option between the command name and its first argument
+(if any). Due to this, the argument to `--run' may not use traditional
+`tar' option syntax, i.e., the following is wrong:
+
+ # Wrong!
+ genfile --run='tar cf foo bar'
+
+Use the following syntax instead:
+
+ genfile --run='tar -cf foo bar' ACTIONS...
+
+ The above command line is equivalent to
+
+ genfile ACTIONS... -- tar -cf foo bar
+
+ Notice, that the use of compatibility mode is deprecated.
+
\1f
-File: tar.info, Node: Free Software Needs Free Documentation, Next: Copying This Manual, Prev: Genfile, Up: Top
+File: tar.info, Node: Free Software Needs Free Documentation, Next: GNU Free Documentation License, Prev: Genfile, Up: Top
Appendix F Free Software Needs Free Documentation
*************************************************
`http://www.fsf.org/doc/other-free-books.html'.
\1f
-File: tar.info, Node: Copying This Manual, Next: Index of Command Line Options, Prev: Free Software Needs Free Documentation, Up: Top
-
-Appendix G Copying This Manual
-******************************
-
-* Menu:
-
-* GNU Free Documentation License:: License for copying this manual
-
-\1f
-File: tar.info, Node: GNU Free Documentation License, Up: Copying This Manual
+File: tar.info, Node: GNU Free Documentation License, Next: Index of Command Line Options, Prev: Free Software Needs Free Documentation, Up: Top
-G.1 GNU Free Documentation License
-==================================
+Appendix G GNU Free Documentation License
+*****************************************
- Version 1.2, November 2002
+ Version 1.3, 3 November 2008
- Copyright (C) 2000,2001,2002 Free Software Foundation, Inc.
- 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
+ Copyright (C) 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.
+ `http://fsf.org/'
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
Page" means the text near the most prominent appearance of the
work's title, preceding the beginning of the body of the text.
+ The "publisher" means any person or entity that distributes copies
+ of the Document to the public.
+
A section "Entitled XYZ" means a named subunit of the Document
whose title either is precisely XYZ or contains XYZ in parentheses
following text that translates XYZ in another language. (Here XYZ
9. TERMINATION
You may not copy, modify, sublicense, or distribute the Document
- except as expressly provided for under this License. Any other
- attempt to copy, modify, sublicense or distribute the Document is
- void, and will automatically terminate your rights under this
- License. However, parties who have received copies, or rights,
- from you under this License will not have their licenses
- terminated so long as such parties remain in full compliance.
+ except as expressly provided under this License. Any attempt
+ otherwise to copy, modify, sublicense, or distribute it is void,
+ and will automatically terminate your rights under this License.
+
+ However, if you cease all violation of this License, then your
+ license from a particular copyright holder is reinstated (a)
+ provisionally, unless and until the copyright holder explicitly
+ and finally terminates your license, and (b) permanently, if the
+ copyright holder fails to notify you of the violation by some
+ reasonable means prior to 60 days after the cessation.
+
+ Moreover, your license from a particular copyright holder is
+ reinstated permanently if the copyright holder notifies you of the
+ violation by some reasonable means, this is the first time you have
+ received notice of violation of this License (for any work) from
+ that copyright holder, and you cure the violation prior to 30 days
+ after your receipt of the notice.
+
+ Termination of your rights under this section does not terminate
+ the licenses of parties who have received copies or rights from
+ you under this License. If your rights have been terminated and
+ not permanently reinstated, receipt of a copy of some or all of
+ the same material does not give you any rights to use it.
10. FUTURE REVISIONS OF THIS LICENSE
published (not as a draft) by the Free Software Foundation. If
the Document does not specify a version number of this License,
you may choose any version ever published (not as a draft) by the
- Free Software Foundation.
+ Free Software Foundation. If the Document specifies that a proxy
+ can decide which future versions of this License can be used, that
+ proxy's public statement of acceptance of a version permanently
+ authorizes you to choose that version for the Document.
+
+ 11. RELICENSING
+
+ "Massive Multiauthor Collaboration Site" (or "MMC Site") means any
+ World Wide Web server that publishes copyrightable works and also
+ provides prominent facilities for anybody to edit those works. A
+ public wiki that anybody can edit is an example of such a server.
+ A "Massive Multiauthor Collaboration" (or "MMC") contained in the
+ site means any set of copyrightable works thus published on the MMC
+ site.
+
+ "CC-BY-SA" means the Creative Commons Attribution-Share Alike 3.0
+ license published by Creative Commons Corporation, a not-for-profit
+ corporation with a principal place of business in San Francisco,
+ California, as well as future copyleft versions of that license
+ published by that same organization.
+
+ "Incorporate" means to publish or republish a Document, in whole or
+ in part, as part of another Document.
-G.1.1 ADDENDUM: How to use this License for your documents
-----------------------------------------------------------
+ An MMC is "eligible for relicensing" if it is licensed under this
+ License, and if all works that were first published under this
+ License somewhere other than this MMC, and subsequently
+ incorporated in whole or in part into the MMC, (1) had no cover
+ texts or invariant sections, and (2) were thus incorporated prior
+ to November 1, 2008.
+
+ The operator of an MMC Site may republish an MMC contained in the
+ site under CC-BY-SA on the same site at any time before August 1,
+ 2009, provided the MMC is eligible for relicensing.
+
+
+ADDENDUM: How to use this License for your documents
+====================================================
To use this License in a document you have written, include a copy of
the License in the document and put the following copyright and license
Copyright (C) YEAR YOUR NAME.
Permission is granted to copy, distribute and/or modify this document
- under the terms of the GNU Free Documentation License, Version 1.2
+ under the terms of the GNU Free Documentation License, Version 1.3
or any later version published by the Free Software Foundation;
with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
Texts. A copy of the license is included in the section entitled ``GNU
permit their use in free software.
\1f
-File: tar.info, Node: Index of Command Line Options, Next: Index, Prev: Copying This Manual, Up: Top
+File: tar.info, Node: Index of Command Line Options, Next: Index, Prev: GNU Free Documentation License, Up: Top
Appendix H Index of Command Line Options
****************************************
This appendix contains an index of all GNU `tar' long command line
options. The options are listed without the preceding double-dash. For
-a cross-reference of short command line options, *note Short Option
+a cross-reference of short command line options, see *note Short Option
Summary::.
\0\b[index\0\b]
* Menu:
-* absolute-names: absolute. (line 8)
+* --keep-directory-symlink, summary: Option Summary. (line 359)
+* absolute-names: absolute. (line 10)
* absolute-names, summary: Option Summary. (line 6)
-* add-file: files. (line 84)
-* after-date: after. (line 26)
-* after-date, summary: Option Summary. (line 12)
+* add-file: files. (line 60)
+* after-date: after. (line 24)
+* after-date, summary: Option Summary. (line 13)
* anchored: controlling pattern-matching.
(line 79)
-* anchored, summary: Option Summary. (line 15)
-* append: append. (line 8)
+* anchored, summary: Option Summary. (line 16)
+* append <1>: appending files. (line 6)
+* append: append. (line 6)
* append, summary: Operation Summary. (line 6)
-* atime-preserve: Attributes. (line 14)
-* atime-preserve, summary: Option Summary. (line 19)
-* auto-compress: gzip. (line 76)
-* auto-compress, summary: Option Summary. (line 65)
+* atime-preserve: Attributes. (line 10)
+* atime-preserve, summary: Option Summary. (line 20)
+* auto-compress: gzip. (line 155)
+* auto-compress, summary: Option Summary. (line 66)
* backup: backup. (line 41)
-* backup, summary: Option Summary. (line 71)
+* backup, summary: Option Summary. (line 72)
* block-number: verbose. (line 115)
-* block-number, summary: Option Summary. (line 76)
+* block-number, summary: Option Summary. (line 77)
* blocking-factor: Blocking Factor. (line 8)
-* blocking-factor, summary: Option Summary. (line 82)
-* bzip2: gzip. (line 130)
-* bzip2, summary: Option Summary. (line 87)
+* blocking-factor, summary: Option Summary. (line 83)
+* bzip2, summary: Option Summary. (line 88)
* catenate: concatenate. (line 6)
* catenate, summary: Operation Summary. (line 10)
-* check-device, described: Incremental Dumps. (line 99)
-* check-device, summary: Option Summary. (line 92)
-* check-links, described: hard links. (line 33)
-* check-links, summary: Option Summary. (line 143)
+* check-device, described: Incremental Dumps. (line 108)
+* check-device, summary: Option Summary. (line 93)
+* check-links, described: hard links. (line 31)
+* check-links, summary: Option Summary. (line 144)
* checkpoint: checkpoints. (line 6)
* checkpoint, defined: checkpoints. (line 13)
-* checkpoint, summary: Option Summary. (line 97)
+* checkpoint, summary: Option Summary. (line 98)
* checkpoint-action: checkpoints. (line 6)
* checkpoint-action, defined: checkpoints. (line 22)
-* checkpoint-action, summary: Option Summary. (line 105)
-* compare: compare. (line 8)
+* checkpoint-action, summary: Option Summary. (line 106)
+* compare: compare. (line 6)
* compare, summary: Operation Summary. (line 14)
-* compress: gzip. (line 141)
-* compress, summary: Option Summary. (line 152)
+* compress: gzip. (line 113)
+* compress, summary: Option Summary. (line 153)
* concatenate: concatenate. (line 6)
* concatenate, summary: Operation Summary. (line 20)
-* confirmation, summary: Option Summary. (line 159)
+* confirmation, summary: Option Summary. (line 160)
* create, additional options: create options. (line 6)
* create, complementary notes: Basic tar. (line 11)
* create, introduced: Creating the archive.
* create, using with --verify: verify. (line 24)
* delay-directory-restore: Directory Modification Times and Permissions.
(line 62)
-* delay-directory-restore, summary: Option Summary. (line 162)
-* delete: delete. (line 8)
+* delay-directory-restore, summary: Option Summary. (line 163)
+* delete: delete. (line 6)
* delete, summary: Operation Summary. (line 29)
+* delete, using before -append: append. (line 47)
* dereference: dereference. (line 6)
-* dereference, summary: Option Summary. (line 167)
+* dereference, summary: Option Summary. (line 168)
* diff, summary: Operation Summary. (line 33)
* directory: directory. (line 11)
-* directory, summary: Option Summary. (line 173)
-* directory, using in --files-from argument: files. (line 60)
-* exclude: exclude. (line 11)
+* directory, summary: Option Summary. (line 174)
+* exclude: exclude. (line 6)
* exclude, potential problems with: problems with exclude.
(line 6)
-* exclude, summary: Option Summary. (line 180)
-* exclude-caches: exclude. (line 96)
-* exclude-caches, summary: Option Summary. (line 189)
-* exclude-caches-all: exclude. (line 104)
-* exclude-caches-all, summary: Option Summary. (line 202)
-* exclude-caches-under: exclude. (line 100)
-* exclude-caches-under, summary: Option Summary. (line 196)
-* exclude-from: exclude. (line 22)
-* exclude-from, summary: Option Summary. (line 184)
-* exclude-tag: exclude. (line 113)
-* exclude-tag, summary: Option Summary. (line 206)
-* exclude-tag-all: exclude. (line 121)
-* exclude-tag-all, summary: Option Summary. (line 214)
-* exclude-tag-under: exclude. (line 117)
-* exclude-tag-under, summary: Option Summary. (line 210)
-* exclude-vcs: exclude. (line 39)
-* exclude-vcs, summary: Option Summary. (line 218)
-* extract: extract. (line 8)
-* extract, additional options: extract options. (line 8)
+* exclude, summary: Option Summary. (line 181)
+* exclude-backups: exclude. (line 82)
+* exclude-backups, summary: Option Summary. (line 185)
+* exclude-caches: exclude. (line 105)
+* exclude-caches, summary: Option Summary. (line 193)
+* exclude-caches-all: exclude. (line 113)
+* exclude-caches-all, summary: Option Summary. (line 206)
+* exclude-caches-under: exclude. (line 109)
+* exclude-caches-under, summary: Option Summary. (line 200)
+* exclude-from: exclude. (line 6)
+* exclude-from, summary: Option Summary. (line 188)
+* exclude-tag: exclude. (line 122)
+* exclude-tag, summary: Option Summary. (line 210)
+* exclude-tag-all: exclude. (line 130)
+* exclude-tag-all, summary: Option Summary. (line 220)
+* exclude-tag-under: exclude. (line 126)
+* exclude-tag-under, summary: Option Summary. (line 215)
+* exclude-vcs: exclude. (line 37)
+* exclude-vcs, summary: Option Summary. (line 224)
+* extract: extract. (line 6)
+* extract, additional options: extract options. (line 6)
* extract, complementary notes: Basic tar. (line 48)
* extract, summary: Operation Summary. (line 37)
* extract, using with --listed-incremental: Incremental Dumps.
- (line 112)
-* file, short description: file. (line 17)
-* file, summary: Option Summary. (line 224)
+ (line 121)
+* file: file. (line 6)
+* file, short description: file. (line 15)
+* file, summary: Option Summary. (line 230)
* file, tutorial: file tutorial. (line 6)
* files-from: files. (line 14)
-* files-from, summary: Option Summary. (line 230)
+* files-from, summary: Option Summary. (line 236)
* force-local, short description: Device. (line 70)
-* force-local, summary: Option Summary. (line 236)
-* format, summary: Option Summary. (line 241)
+* force-local, summary: Option Summary. (line 242)
+* format, summary: Option Summary. (line 247)
+* full-time, summary: Option Summary. (line 272)
* get, summary: Operation Summary. (line 42)
-* group: override. (line 73)
-* group, summary: Option Summary. (line 266)
-* gunzip, summary: Option Summary. (line 274)
-* gzip: gzip. (line 96)
-* gzip, summary: Option Summary. (line 274)
-* hard-dereference, described: hard links. (line 61)
-* hard-dereference, summary: Option Summary. (line 282)
+* group: override. (line 88)
+* group, summary: Option Summary. (line 290)
+* gunzip, summary: Option Summary. (line 298)
+* gzip: gzip. (line 91)
+* gzip, summary: Option Summary. (line 298)
+* hard-dereference, described: hard links. (line 59)
+* hard-dereference, summary: Option Summary. (line 306)
* help: help tutorial. (line 6)
* help, introduction: help. (line 26)
-* help, summary: Option Summary. (line 288)
+* help, summary: Option Summary. (line 312)
* ignore-case: controlling pattern-matching.
(line 86)
-* ignore-case, summary: Option Summary. (line 293)
+* ignore-case, summary: Option Summary. (line 317)
* ignore-command-error: Writing to an External Program.
- (line 82)
-* ignore-command-error, summary: Option Summary. (line 297)
+ (line 110)
+* ignore-command-error, summary: Option Summary. (line 321)
* ignore-failed-read: Ignore Failed Read. (line 7)
-* ignore-failed-read, summary: Option Summary. (line 301)
+* ignore-failed-read, summary: Option Summary. (line 325)
* ignore-zeros: Ignore Zeros. (line 6)
* ignore-zeros, short description: Blocking Factor. (line 156)
-* ignore-zeros, summary: Option Summary. (line 305)
-* incremental, summary: Option Summary. (line 310)
-* incremental, using with --list: Incremental Dumps. (line 177)
-* index-file, summary: Option Summary. (line 317)
+* ignore-zeros, summary: Option Summary. (line 329)
+* incremental, summary: Option Summary. (line 334)
+* incremental, using with --list: Incremental Dumps. (line 186)
+* index-file, summary: Option Summary. (line 341)
* info-script: Multi-Volume Archives.
- (line 80)
-* info-script, short description: Device. (line 104)
-* info-script, summary: Option Summary. (line 320)
+ (line 88)
+* info-script, short description: Device. (line 122)
+* info-script, summary: Option Summary. (line 344)
* interactive: interactive. (line 14)
-* interactive, summary: Option Summary. (line 328)
+* interactive, summary: Option Summary. (line 352)
* keep-newer-files: Keep Newer Files. (line 6)
-* keep-newer-files, summary: Option Summary. (line 335)
-* keep-old-files: Keep Old Files. (line 6)
+* keep-newer-files, summary: Option Summary. (line 372)
+* keep-old-files: Keep Old Files. (line 9)
* keep-old-files, introduced: Dealing with Old Files.
(line 16)
-* keep-old-files, summary: Option Summary. (line 339)
-* label: label. (line 8)
-* label, summary: Option Summary. (line 344)
+* keep-old-files, summary: Option Summary. (line 376)
+* label <1>: label. (line 6)
+* label: Tape Files. (line 6)
+* label, summary: Option Summary. (line 384)
+* level, described: Incremental Dumps. (line 76)
+* level, summary: Option Summary. (line 391)
* list: list. (line 6)
* list, summary: Operation Summary. (line 46)
-* list, using with --incremental: Incremental Dumps. (line 177)
-* list, using with --listed-incremental: Incremental Dumps. (line 177)
+* list, using with --incremental: Incremental Dumps. (line 186)
+* list, using with --listed-incremental: Incremental Dumps. (line 186)
* list, using with --verbose: list. (line 30)
* list, using with file name arguments: list. (line 68)
-* listed-incremental: Incremental Dumps. (line 14)
-* listed-incremental, summary: Option Summary. (line 351)
+* listed-incremental, described: Incremental Dumps. (line 14)
+* listed-incremental, summary: Option Summary. (line 401)
* listed-incremental, using with --extract: Incremental Dumps.
- (line 112)
-* listed-incremental, using with --list: Incremental Dumps. (line 177)
-* lzma: gzip. (line 134)
-* lzma, summary: Option Summary. (line 359)
-* lzop: gzip. (line 138)
+ (line 121)
+* listed-incremental, using with --list: Incremental Dumps. (line 186)
+* lzip: gzip. (line 104)
+* lzip, summary: Option Summary. (line 409)
+* lzma: gzip. (line 107)
+* lzma, summary: Option Summary. (line 413)
+* lzop: gzip. (line 110)
* mode: override. (line 14)
-* mode, summary: Option Summary. (line 368)
+* mode, summary: Option Summary. (line 421)
* mtime: override. (line 29)
-* mtime, summary: Option Summary. (line 374)
+* mtime, summary: Option Summary. (line 427)
* multi-volume: Multi-Volume Archives.
(line 6)
* multi-volume, short description: Device. (line 88)
-* multi-volume, summary: Option Summary. (line 383)
+* multi-volume, summary: Option Summary. (line 436)
* new-volume-script: Multi-Volume Archives.
- (line 80)
-* new-volume-script, short description: Device. (line 104)
-* new-volume-script, summary: Option Summary. (line 320)
-* newer: after. (line 26)
-* newer, summary: Option Summary. (line 391)
-* newer-mtime: after. (line 37)
-* newer-mtime, summary: Option Summary. (line 399)
+ (line 88)
+* new-volume-script, short description: Device. (line 122)
+* new-volume-script, summary: Option Summary. (line 344)
+* newer: after. (line 24)
+* newer, summary: Option Summary. (line 444)
+* newer-mtime: after. (line 35)
+* newer-mtime, summary: Option Summary. (line 452)
* no-anchored: controlling pattern-matching.
(line 79)
-* no-anchored, summary: Option Summary. (line 404)
-* no-auto-compress, summary: Option Summary. (line 408)
-* no-check-device, described: Incremental Dumps. (line 95)
-* no-check-device, summary: Option Summary. (line 412)
+* no-anchored, summary: Option Summary. (line 457)
+* no-auto-compress, summary: Option Summary. (line 461)
+* no-check-device, described: Incremental Dumps. (line 104)
+* no-check-device, summary: Option Summary. (line 465)
* no-delay-directory-restore: Directory Modification Times and Permissions.
(line 68)
-* no-delay-directory-restore, summary: Option Summary. (line 417)
+* no-delay-directory-restore, summary: Option Summary. (line 470)
* no-ignore-case: controlling pattern-matching.
(line 86)
-* no-ignore-case, summary: Option Summary. (line 423)
+* no-ignore-case, summary: Option Summary. (line 476)
* no-ignore-command-error: Writing to an External Program.
- (line 87)
-* no-ignore-command-error, summary: Option Summary. (line 426)
+ (line 115)
+* no-ignore-command-error, summary: Option Summary. (line 479)
* no-null, described: nul. (line 15)
-* no-null, summary: Option Summary. (line 430)
-* no-overwrite-dir, summary: Option Summary. (line 435)
-* no-quote-chars, summary: Option Summary. (line 439)
-* no-recursion: recurse. (line 13)
-* no-recursion, summary: Option Summary. (line 444)
-* no-same-owner: Attributes. (line 67)
-* no-same-owner, summary: Option Summary. (line 448)
-* no-same-permissions, summary: Option Summary. (line 454)
+* no-null, summary: Option Summary. (line 483)
+* no-overwrite-dir, summary: Option Summary. (line 488)
+* no-quote-chars, summary: Option Summary. (line 492)
+* no-recursion: recurse. (line 11)
+* no-recursion, summary: Option Summary. (line 497)
+* no-same-owner: Attributes. (line 63)
+* no-same-owner, summary: Option Summary. (line 501)
+* no-same-permissions, summary: Option Summary. (line 507)
+* no-seek, summary: Option Summary. (line 512)
* no-unquote: Selecting Archive Members.
(line 42)
-* no-unquote, summary: Option Summary. (line 459)
+* no-unquote, summary: Option Summary. (line 517)
* no-wildcards: controlling pattern-matching.
(line 41)
-* no-wildcards, summary: Option Summary. (line 463)
+* no-wildcards, summary: Option Summary. (line 521)
* no-wildcards-match-slash: controlling pattern-matching.
(line 92)
-* no-wildcards-match-slash, summary: Option Summary. (line 466)
+* no-wildcards-match-slash, summary: Option Summary. (line 524)
* null, described: nul. (line 11)
-* null, summary: Option Summary. (line 469)
-* numeric-owner: Attributes. (line 73)
-* numeric-owner, summary: Option Summary. (line 475)
-* occurrence, summary: Option Summary. (line 492)
-* old-archive, summary: Option Summary. (line 506)
-* one-file-system: one. (line 16)
-* one-file-system, summary: Option Summary. (line 509)
+* null, summary: Option Summary. (line 527)
+* numeric-owner: Attributes. (line 69)
+* numeric-owner, summary: Option Summary. (line 533)
+* occurrence, described: append. (line 34)
+* occurrence, summary: Option Summary. (line 550)
+* old-archive, summary: Option Summary. (line 564)
+* one-file-system: one. (line 14)
+* one-file-system, summary: Option Summary. (line 567)
* overwrite: Overwrite Old Files. (line 6)
* overwrite, introduced: Dealing with Old Files.
- (line 22)
-* overwrite, summary: Option Summary. (line 514)
+ (line 32)
+* overwrite, summary: Option Summary. (line 572)
* overwrite-dir: Overwrite Old Files. (line 28)
* overwrite-dir, introduced: Dealing with Old Files.
(line 6)
-* overwrite-dir, summary: Option Summary. (line 518)
+* overwrite-dir, summary: Option Summary. (line 576)
* owner: override. (line 57)
-* owner, summary: Option Summary. (line 522)
+* owner, summary: Option Summary. (line 580)
* pax-option: PAX keywords. (line 6)
-* pax-option, summary: Option Summary. (line 531)
-* portability, summary: Option Summary. (line 537)
-* posix, summary: Option Summary. (line 541)
-* preserve: Attributes. (line 126)
-* preserve, summary: Option Summary. (line 544)
+* pax-option, summary: Option Summary. (line 588)
+* portability, summary: Option Summary. (line 594)
+* posix, summary: Option Summary. (line 598)
+* preserve: Attributes. (line 122)
+* preserve, summary: Option Summary. (line 601)
* preserve-order: Same Order. (line 6)
-* preserve-order, summary: Option Summary. (line 548)
+* preserve-order, summary: Option Summary. (line 605)
* preserve-permissions: Setting Access Permissions.
(line 10)
-* preserve-permissions, short description: Attributes. (line 113)
-* preserve-permissions, summary: Option Summary. (line 551)
-* quote-chars, summary: Option Summary. (line 561)
+* preserve-permissions, short description: Attributes. (line 109)
+* preserve-permissions, summary: Option Summary. (line 608)
+* quote-chars, summary: Option Summary. (line 618)
* quoting-style: quoting styles. (line 38)
-* quoting-style, summary: Option Summary. (line 565)
+* quoting-style, summary: Option Summary. (line 622)
* read-full-records <1>: read full records. (line 6)
-* read-full-records: Reading. (line 8)
+* read-full-records: Reading. (line 6)
* read-full-records, short description: Blocking Factor. (line 172)
-* read-full-records, summary: Option Summary. (line 572)
-* record-size, summary: Option Summary. (line 577)
-* recursion: recurse. (line 24)
-* recursion, summary: Option Summary. (line 581)
+* read-full-records, summary: Option Summary. (line 629)
+* record-size, summary: Option Summary. (line 634)
+* recursion: recurse. (line 22)
+* recursion, summary: Option Summary. (line 641)
* recursive-unlink: Recursive Unlink. (line 6)
-* recursive-unlink, summary: Option Summary. (line 585)
+* recursive-unlink, summary: Option Summary. (line 645)
* remove-files: remove files. (line 6)
-* remove-files, summary: Option Summary. (line 590)
-* restrict, summary: Option Summary. (line 594)
-* rmt-command, summary: Option Summary. (line 599)
+* remove-files, summary: Option Summary. (line 650)
+* restrict, summary: Option Summary. (line 654)
+* rmt-command, summary: Option Summary. (line 659)
* rsh-command: Device. (line 73)
-* rsh-command, summary: Option Summary. (line 603)
+* rsh-command, summary: Option Summary. (line 663)
* same-order: Same Order. (line 6)
-* same-order, summary: Option Summary. (line 607)
-* same-owner: Attributes. (line 48)
-* same-owner, summary: Option Summary. (line 615)
+* same-order, summary: Option Summary. (line 667)
+* same-owner: Attributes. (line 44)
+* same-owner, summary: Option Summary. (line 675)
* same-permissions: Setting Access Permissions.
(line 10)
-* same-permissions, short description: Attributes. (line 113)
-* same-permissions, summary: Option Summary. (line 551)
-* seek, summary: Option Summary. (line 624)
+* same-permissions, short description: Attributes. (line 109)
+* same-permissions, summary: Option Summary. (line 608)
+* seek, summary: Option Summary. (line 684)
* show-defaults: defaults. (line 6)
-* show-defaults, summary: Option Summary. (line 631)
+* show-defaults, summary: Option Summary. (line 693)
* show-omitted-dirs: verbose. (line 107)
-* show-omitted-dirs, summary: Option Summary. (line 640)
+* show-omitted-dirs, summary: Option Summary. (line 705)
+* show-snapshot-field-ranges: Snapshot Files. (line 113)
+* show-snapshot-field-ranges, summary: Option Summary. (line 709)
* show-stored-names: list. (line 60)
-* show-stored-names, summary: Option Summary. (line 644)
+* show-stored-names, summary: Option Summary. (line 714)
* show-transformed-names: transform. (line 45)
-* show-transformed-names, summary: Option Summary. (line 644)
+* show-transformed-names, summary: Option Summary. (line 714)
+* skip-old-files, introduced: Dealing with Old Files.
+ (line 28)
+* skip-old-files, summary: Option Summary. (line 722)
* sparse: sparse. (line 22)
-* sparse, summary: Option Summary. (line 652)
+* sparse, summary: Option Summary. (line 734)
* sparse-version: sparse. (line 57)
-* sparse-version, summary: Option Summary. (line 657)
+* sparse-version, summary: Option Summary. (line 739)
* starting-file: Starting File. (line 6)
-* starting-file, summary: Option Summary. (line 662)
+* starting-file, summary: Option Summary. (line 744)
* strip-components: transform. (line 25)
-* strip-components, summary: Option Summary. (line 668)
+* strip-components, summary: Option Summary. (line 750)
* suffix: backup. (line 68)
-* suffix, summary: Option Summary. (line 677)
+* suffix, summary: Option Summary. (line 759)
* tape-length: Multi-Volume Archives.
(line 33)
* tape-length, short description: Device. (line 96)
-* tape-length, summary: Option Summary. (line 683)
-* test-label: label. (line 37)
-* test-label, summary: Option Summary. (line 688)
+* tape-length, summary: Option Summary. (line 763)
+* test-label: label. (line 35)
+* test-label, summary: Option Summary. (line 772)
* to-command: Writing to an External Program.
(line 9)
-* to-command, summary: Option Summary. (line 692)
+* to-command, summary: Option Summary. (line 776)
* to-stdout: Writing to Standard Output.
(line 14)
-* to-stdout, summary: Option Summary. (line 696)
+* to-stdout, summary: Option Summary. (line 780)
* totals: verbose. (line 46)
-* totals, summary: Option Summary. (line 701)
-* touch <1>: Attributes. (line 37)
+* totals, summary: Option Summary. (line 785)
+* touch <1>: Attributes. (line 33)
* touch: Data Modification Times.
(line 15)
-* touch, summary: Option Summary. (line 706)
+* touch, summary: Option Summary. (line 790)
* transform: transform. (line 74)
-* transform, summary: Option Summary. (line 712)
-* uncompress: gzip. (line 141)
-* uncompress, summary: Option Summary. (line 152)
-* ungzip: gzip. (line 96)
-* ungzip, summary: Option Summary. (line 274)
+* transform, summary: Option Summary. (line 796)
+* uncompress: gzip. (line 113)
+* uncompress, summary: Option Summary. (line 153)
+* ungzip: gzip. (line 91)
+* ungzip, summary: Option Summary. (line 298)
* unlink-first: Unlink First. (line 6)
* unlink-first, introduced: Dealing with Old Files.
- (line 42)
-* unlink-first, summary: Option Summary. (line 732)
+ (line 52)
+* unlink-first, summary: Option Summary. (line 816)
* unquote: Selecting Archive Members.
(line 39)
-* unquote, summary: Option Summary. (line 738)
-* update: update. (line 8)
+* unquote, summary: Option Summary. (line 822)
+* update <1>: how to update. (line 6)
+* update: update. (line 6)
* update, summary: Operation Summary. (line 50)
* usage: help. (line 53)
-* use-compress-program: gzip. (line 146)
-* use-compress-program, summary: Option Summary. (line 742)
-* utc, summary: Option Summary. (line 746)
+* use-compress-program: gzip. (line 177)
+* use-compress-program, summary: Option Summary. (line 826)
+* utc, summary: Option Summary. (line 831)
* verbose: verbose. (line 18)
* verbose, introduced: verbose tutorial. (line 6)
-* verbose, summary: Option Summary. (line 750)
+* verbose, summary: Option Summary. (line 835)
* verbose, using with --create: create verbose. (line 6)
* verbose, using with --list: list. (line 30)
* verify, short description: verify. (line 8)
-* verify, summary: Option Summary. (line 757)
+* verify, summary: Option Summary. (line 842)
* verify, using with --create: verify. (line 24)
* version: help. (line 6)
-* version, summary: Option Summary. (line 762)
+* version, summary: Option Summary. (line 847)
* volno-file: Multi-Volume Archives.
- (line 71)
-* volno-file, summary: Option Summary. (line 767)
+ (line 79)
+* volno-file, summary: Option Summary. (line 852)
+* warning, explained: warnings. (line 12)
+* warning, summary: Option Summary. (line 857)
* wildcards: controlling pattern-matching.
(line 38)
-* wildcards, summary: Option Summary. (line 772)
+* wildcards, summary: Option Summary. (line 862)
* wildcards-match-slash: controlling pattern-matching.
(line 92)
-* wildcards-match-slash, summary: Option Summary. (line 776)
+* wildcards-match-slash, summary: Option Summary. (line 866)
* xform: transform. (line 74)
-* xform, summary: Option Summary. (line 712)
-
-\1f
-File: tar.info, Node: Index, Prev: Index of Command Line Options, Up: Top
-
-Appendix I Index
-****************
-
-\0\b[index\0\b]
-* Menu:
-
-* abbreviations for months: Calendar date items. (line 38)
-* absolute file names: Remote Tape Server. (line 17)
-* Adding archives to an archive: concatenate. (line 6)
-* Adding files to an Archive: appending files. (line 8)
-* ADMINISTRATOR: General-Purpose Variables.
- (line 7)
-* Age, excluding files by: after. (line 8)
-* ago in date strings: Relative items in date strings.
- (line 23)
-* am in date strings: Time of day items. (line 22)
-* Appending files to an Archive: appending files. (line 8)
-* Arch, excluding files: exclude. (line 39)
-* archive: Definitions. (line 6)
-* Archive creation: file. (line 36)
-* archive member: Definitions. (line 15)
-* Archive Name: file. (line 8)
-* Archive, creation of: create. (line 8)
-* Archives, Appending files to: appending files. (line 8)
-* Archiving Directories: create dir. (line 6)
-* archiving files: Top. (line 24)
-* ARGP_HELP_FMT, environment variable: Configuring Help Summary.
- (line 21)
-* authors of get_date: Authors of get_date. (line 6)
-* Avoiding recursion in directories: recurse. (line 8)
-* backup options: backup. (line 6)
-* backup suffix: backup. (line 68)
-* BACKUP_DIRS: General-Purpose Variables.
- (line 29)
-* BACKUP_FILES: General-Purpose Variables.
- (line 55)
-* BACKUP_HOUR: General-Purpose Variables.
- (line 11)
-* backups: backup. (line 41)
-* Bazaar, excluding files: exclude. (line 39)
-* beginning of time, for POSIX: Seconds since the Epoch.
- (line 13)
-* bell, checkpoint action: checkpoints. (line 65)
-* Bellovin, Steven M.: Authors of get_date. (line 6)
-* Berets, Jim: Authors of get_date. (line 6)
-* Berry, K.: Authors of get_date. (line 14)
-* Block number where error occurred: verbose. (line 115)
-* BLOCKING: General-Purpose Variables.
- (line 25)
-* blocking factor: Blocking Factor. (line 194)
-* Blocking Factor: Blocking Factor. (line 6)
-* Blocks per record: Blocking Factor. (line 6)
-* bug reports: Reports. (line 6)
-* Bytes per record: Blocking Factor. (line 6)
-* bzip2: gzip. (line 6)
-* calendar date item: Calendar date items. (line 6)
-* case, ignored in dates: General date syntax. (line 64)
-* cat vs concatenate: concatenate. (line 63)
-* Changing directory mid-stream: directory. (line 6)
-* Character class, excluding characters from: wildcards. (line 34)
-* checkpoints, defined: checkpoints. (line 6)
-* Choosing an archive file: file. (line 8)
-* comments, in dates: General date syntax. (line 64)
-* compress: gzip. (line 6)
-* Compressed archives: gzip. (line 6)
-* concatenate vs cat: concatenate. (line 63)
-* Concatenating Archives: concatenate. (line 6)
-* corrupted archives <1>: gzip. (line 115)
-* corrupted archives: Full Dumps. (line 8)
-* Creation of the archive: create. (line 8)
-* CVS, excluding files: exclude. (line 39)
-* Darcs, excluding files: exclude. (line 39)
-* DAT blocking: Blocking Factor. (line 204)
-* Data Modification time, excluding files by: after. (line 8)
-* Data modification times of extracted files: Data Modification Times.
- (line 6)
-* date format, ISO 8601: Calendar date items. (line 30)
-* date input formats: Date input formats. (line 6)
-* day in date strings: Relative items in date strings.
- (line 15)
-* day of week item: Day of week items. (line 6)
-* Deleting files from an archive: delete. (line 8)
-* Deleting from tape archives: delete. (line 19)
-* dereferencing hard links: hard links. (line 8)
-* Descending directories, avoiding: recurse. (line 8)
-* Device numbers, changing: Fixing Snapshot Files.
- (line 6)
-* Device numbers, using in incremental backups: Incremental Dumps.
- (line 81)
-* Directories, Archiving: create dir. (line 6)
-* Directories, avoiding recursion: recurse. (line 8)
-* Directory, changing mid-stream: directory. (line 6)
-* DIRLIST: General-Purpose Variables.
- (line 51)
-* displacement of dates: Relative items in date strings.
- (line 6)
-* doc-opt-col: Configuring Help Summary.
- (line 94)
-* dot, checkpoint action: checkpoints. (line 80)
-* Double-checking a write operation: verify. (line 6)
-* DUMP_BEGIN: User Hooks. (line 32)
-* DUMP_END: User Hooks. (line 36)
-* DUMP_REMIND_SCRIPT: General-Purpose Variables.
- (line 102)
-* dumps, full: Full Dumps. (line 8)
-* dup-args: Configuring Help Summary.
- (line 51)
-* dup-args-note: Configuring Help Summary.
- (line 68)
-* echo, checkpoint action: checkpoints. (line 25)
-* Eggert, Paul: Authors of get_date. (line 6)
-* End-of-archive blocks, ignoring: Ignore Zeros. (line 6)
-* End-of-archive info script: Multi-Volume Archives.
- (line 80)
-* entry: Naming tar Archives. (line 11)
-* epoch, for POSIX: Seconds since the Epoch.
- (line 13)
-* Error message, block number of: verbose. (line 125)
-* Exabyte blocking: Blocking Factor. (line 204)
-* exclude: exclude. (line 14)
-* exclude-caches: exclude. (line 84)
-* exclude-from: exclude. (line 27)
-* exclude-tag: exclude. (line 107)
-* Excluding characters from a character class: wildcards. (line 34)
-* Excluding file by age: after. (line 8)
-* Excluding files by file system: exclude. (line 8)
-* Excluding files by name and pattern: exclude. (line 8)
-* Exec Mode, genfile: Exec Mode. (line 6)
-* exec, checkpoint action: checkpoints. (line 96)
-* existing backup method: backup. (line 59)
-* exit status: Synopsis. (line 67)
-* Extraction: extract. (line 8)
-* extraction: Definitions. (line 22)
-* FDL, GNU Free Documentation License: GNU Free Documentation License.
- (line 6)
-* file archival: Top. (line 24)
-* File lists separated by NUL characters: Generate Mode. (line 33)
-* file name: Definitions. (line 15)
-* File Name arguments, alternatives: files. (line 6)
-* File name arguments, using --list with: list. (line 68)
-* File names, excluding files by: exclude. (line 8)
-* File names, terminated by NUL: nul. (line 6)
-* File names, using hard links: hard links. (line 8)
-* File names, using symbolic links: dereference. (line 6)
-* File system boundaries, not crossing: one. (line 6)
-* FILELIST: General-Purpose Variables.
- (line 65)
-* first in date strings: General date syntax. (line 26)
-* format 0, snapshot file: Snapshot Files. (line 23)
-* format 1, snapshot file: Snapshot Files. (line 47)
-* format 2, snapshot file: Snapshot Files. (line 69)
-* Format Options: Format Variations. (line 6)
-* Format Parameters: Format Variations. (line 6)
-* Format, old style: old. (line 6)
-* fortnight in date strings: Relative items in date strings.
- (line 15)
-* free documentation: Free Software Needs Free Documentation.
- (line 6)
-* full dumps: Full Dumps. (line 8)
-* future time stamps: Large or Negative Values.
- (line 6)
-* general date syntax: General date syntax. (line 6)
-* Generate Mode, genfile: Generate Mode. (line 6)
-* genfile: Genfile. (line 6)
-* genfile, create file: Generate Mode. (line 6)
-* genfile, creating sparse files: Generate Mode. (line 55)
-* genfile, generate mode: Generate Mode. (line 6)
-* genfile, reading a list of file names: Generate Mode. (line 22)
-* genfile, seeking to a given offset: Generate Mode. (line 18)
-* get_date: Date input formats. (line 6)
-* Getting program version number: help. (line 6)
-* git, excluding files: exclude. (line 39)
-* GNU archive format: gnu. (line 6)
-* GNU.sparse.major, extended header variable: PAX 1. (line 14)
-* GNU.sparse.map, extended header variable: PAX 0. (line 60)
-* GNU.sparse.minor, extended header variable: PAX 1. (line 17)
-* GNU.sparse.name, extended header variable: PAX 0. (line 68)
-* GNU.sparse.name, extended header variable, in v.1.0: PAX 1. (line 24)
-* GNU.sparse.numblocks, extended header variable: PAX 0. (line 15)
-* GNU.sparse.numbytes, extended header variable: PAX 0. (line 21)
-* GNU.sparse.offset, extended header variable: PAX 0. (line 18)
-* GNU.sparse.realsize, extended header variable: PAX 1. (line 24)
-* GNU.sparse.size, extended header variable: PAX 0. (line 11)
-* gnupg, using with tar: gzip. (line 158)
-* gpg, using with tar: gzip. (line 158)
-* gzip: gzip. (line 6)
-* hard links, dereferencing: hard links. (line 8)
-* header-col: Configuring Help Summary.
- (line 140)
-* hook: User Hooks. (line 13)
-* hour in date strings: Relative items in date strings.
- (line 15)
-* Ignoring end-of-archive blocks: Ignore Zeros. (line 6)
-* Info script: Multi-Volume Archives.
- (line 80)
-* Interactive operation: interactive. (line 6)
-* ISO 8601 date format: Calendar date items. (line 30)
-* items in date strings: General date syntax. (line 6)
-* Labeling an archive: label. (line 6)
-* Labeling multi-volume archives: label. (line 6)
-* Labels on the archive media: label. (line 6)
-* language, in dates: General date syntax. (line 40)
-* Large lists of file names on small machines: Same Order. (line 6)
-* large values: Large or Negative Values.
- (line 6)
-* last DAY: Day of week items. (line 15)
-* last in date strings: General date syntax. (line 26)
-* Listing all tar options: help. (line 26)
-* listing member and file names: list. (line 41)
-* Listing volume label: label. (line 29)
-* Lists of file names: files. (line 6)
-* Local and remote archives: file. (line 73)
-* long-opt-col: Configuring Help Summary.
- (line 86)
-* lzma: gzip. (line 6)
-* lzop: gzip. (line 6)
-* MacKenzie, David: Authors of get_date. (line 6)
-* member: Definitions. (line 15)
-* member name: Definitions. (line 15)
-* Members, replacing with other members: append. (line 49)
-* Mercurial, excluding files: exclude. (line 39)
-* Meyering, Jim: Authors of get_date. (line 6)
-* Middle of the archive, starting in the: Starting File. (line 11)
-* midnight in date strings: Time of day items. (line 22)
-* minute in date strings: Relative items in date strings.
- (line 15)
-* minutes, time zone correction by: Time of day items. (line 30)
-* Modes of extracted files: Setting Access Permissions.
- (line 6)
-* Modification time, excluding files by: after. (line 8)
-* Modification times of extracted files: Data Modification Times.
- (line 6)
-* month in date strings: Relative items in date strings.
- (line 15)
-* month names in date strings: Calendar date items. (line 38)
-* months, written-out: General date syntax. (line 36)
-* MT: General-Purpose Variables.
- (line 69)
-* MT_BEGIN: Magnetic Tape Control.
- (line 11)
-* MT_OFFLINE: Magnetic Tape Control.
- (line 32)
-* MT_REWIND: Magnetic Tape Control.
- (line 21)
-* MT_STATUS: Magnetic Tape Control.
- (line 42)
-* Multi-volume archives: Multi-Volume Archives.
- (line 6)
-* Mutli-volume archives in PAX format, extracting using non-GNU tars: Split Recovery.
- (line 17)
-* Mutli-volume archives, extracting using non-GNU tars: Split Recovery.
- (line 6)
-* Naming an archive: file. (line 8)
-* negative time stamps: Large or Negative Values.
- (line 6)
-* next DAY: Day of week items. (line 15)
-* next in date strings: General date syntax. (line 26)
-* noon in date strings: Time of day items. (line 22)
-* now in date strings: Relative items in date strings.
- (line 33)
-* ntape device: Many. (line 6)
-* NUL terminated file names: nul. (line 6)
-* Number of blocks per record: Blocking Factor. (line 6)
-* Number of bytes per record: Blocking Factor. (line 6)
-* numbered backup method: backup. (line 55)
-* numbers, written-out: General date syntax. (line 26)
-* Obtaining help: help. (line 26)
-* Obtaining total status information: verbose. (line 46)
-* Old GNU archive format: gnu. (line 6)
-* Old GNU sparse format: Old GNU Format. (line 6)
-* Old style archives: old. (line 6)
-* Old style format: old. (line 6)
-* opt-doc-col: Configuring Help Summary.
- (line 126)
-* option syntax, traditional: Old Options. (line 60)
-* Options when reading archives: Reading. (line 6)
-* Options, archive format specifying: Format Variations. (line 6)
-* Options, format specifying: Format Variations. (line 6)
-* ordinal numbers: General date syntax. (line 26)
-* Overwriting old files, prevention: Dealing with Old Files.
- (line 16)
-* pattern, genfile: Generate Mode. (line 39)
-* PAX archive format: posix. (line 6)
-* Permissions of extracted files: Setting Access Permissions.
- (line 6)
-* Pinard, F.: Authors of get_date. (line 14)
-* pm in date strings: Time of day items. (line 22)
-* POSIX archive format: posix. (line 6)
-* Progress information: verbose. (line 83)
-* Protecting old files: Dealing with Old Files.
- (line 26)
-* pure numbers in date strings: Pure numbers in date strings.
- (line 6)
-* RCS, excluding files: exclude. (line 39)
-* Reading file names from a file: files. (line 6)
-* Reading incomplete records: Reading. (line 8)
-* Record Size: Blocking Factor. (line 6)
-* Records, incomplete: Reading. (line 8)
-* Recursion in directories, avoiding: recurse. (line 8)
-* relative items in date strings: Relative items in date strings.
- (line 6)
-* Remote devices: file. (line 62)
-* remote tape drive: Remote Tape Server. (line 6)
-* Removing files from an archive: delete. (line 8)
-* Replacing members with other members: append. (line 49)
-* reporting bugs: Reports. (line 6)
-* RESTORE_BEGIN: User Hooks. (line 39)
-* RESTORE_END: User Hooks. (line 42)
-* Resurrecting files from an archive: extract. (line 8)
-* Retrieving files from an archive: extract. (line 8)
-* return status: Synopsis. (line 67)
-* rmargin: Configuring Help Summary.
- (line 158)
-* rmt: Remote Tape Server. (line 6)
-* RSH: General-Purpose Variables.
- (line 72)
-* RSH_COMMAND: General-Purpose Variables.
- (line 77)
-* Running out of space: Scarce. (line 8)
-* Salz, Rich: Authors of get_date. (line 6)
-* SCCS, excluding files: exclude. (line 39)
-* short-opt-col: Configuring Help Summary.
- (line 78)
-* simple backup method: backup. (line 64)
-* SIMPLE_BACKUP_SUFFIX: backup. (line 68)
-* sleep, checkpoint action: checkpoints. (line 90)
-* SLEEP_MESSAGE: General-Purpose Variables.
- (line 111)
-* SLEEP_TIME: General-Purpose Variables.
- (line 97)
-* Small memory: Scarce. (line 8)
-* snapshot file, format 0: Snapshot Files. (line 23)
-* snapshot file, format 1: Snapshot Files. (line 47)
-* snapshot file, format 2: Snapshot Files. (line 69)
-* snapshot files, editing: Fixing Snapshot Files.
- (line 6)
-* snapshot files, fixing device numbers: Fixing Snapshot Files.
- (line 6)
-* Sparse Files: sparse. (line 6)
-* sparse files v.0.0, extracting with non-GNU tars: Sparse Recovery.
- (line 92)
-* sparse files v.0.1, extracting with non-GNU tars: Sparse Recovery.
- (line 92)
-* sparse files v.1.0, extracting with non-GNU tars: Sparse Recovery.
- (line 17)
-* Sparse files, creating using genfile: Generate Mode. (line 55)
-* sparse files, extracting with non-GNU tars: Sparse Recovery.
- (line 6)
-* sparse formats: Sparse Formats. (line 6)
-* sparse formats, defined: sparse. (line 50)
-* sparse formats, Old GNU: Old GNU Format. (line 6)
-* sparse formats, v.0.0: PAX 0. (line 6)
-* sparse formats, v.0.1: PAX 0. (line 52)
-* sparse formats, v.1.0: PAX 1. (line 6)
-* sparse versions: Sparse Formats. (line 6)
-* Specifying archive members: Selecting Archive Members.
- (line 6)
-* Specifying files to act on: Selecting Archive Members.
- (line 6)
-* Standard input and output: file. (line 41)
-* Standard output, writing extracted files to: Writing to Standard Output.
- (line 6)
-* Storing archives in compressed format: gzip. (line 6)
-* SVN, excluding files: exclude. (line 39)
-* Symbolic link as file name: dereference. (line 6)
-* TAPE: file tutorial. (line 14)
-* tape blocking: Blocking Factor. (line 194)
-* tape marks: Many. (line 44)
-* tape positioning: Many. (line 26)
-* TAPE_FILE: General-Purpose Variables.
- (line 19)
-* Tapes, using --delete and: delete. (line 19)
-* TAR: General-Purpose Variables.
- (line 115)
-* tar: What tar Does. (line 6)
-* tar archive: Definitions. (line 6)
-* Tar archive formats: Formats. (line 6)
-* tar entry: Naming tar Archives. (line 11)
-* tar file: Naming tar Archives. (line 11)
-* tar to a remote device: file. (line 62)
-* tar to standard input and output: file. (line 41)
-* tar-snapshot-edit: Fixing Snapshot Files.
- (line 15)
-* TAR_ARCHIVE, checkpoint script environment: checkpoints. (line 108)
-* TAR_ARCHIVE, info script environment variable: Multi-Volume Archives.
- (line 100)
-* TAR_ATIME, to-command environment: Writing to an External Program.
- (line 49)
-* TAR_BLOCKING_FACTOR, checkpoint script environment: checkpoints.
- (line 111)
-* TAR_BLOCKING_FACTOR, info script environment variable: Multi-Volume Archives.
- (line 103)
-* TAR_CHECKPOINT, checkpoint script environment: checkpoints. (line 114)
-* TAR_CTIME, to-command environment: Writing to an External Program.
- (line 58)
-* TAR_FD, info script environment variable: Multi-Volume Archives.
- (line 117)
-* TAR_FILENAME, to-command environment: Writing to an External Program.
- (line 37)
-* TAR_FILETYPE, to-command environment: Writing to an External Program.
- (line 22)
-* TAR_FORMAT, checkpoint script environment: checkpoints. (line 121)
-* TAR_FORMAT, info script environment variable: Multi-Volume Archives.
- (line 113)
-* TAR_GID, to-command environment: Writing to an External Program.
- (line 67)
-* TAR_GNAME, to-command environment: Writing to an External Program.
- (line 46)
-* TAR_MODE, to-command environment: Writing to an External Program.
- (line 34)
-* TAR_MTIME, to-command environment: Writing to an External Program.
- (line 55)
-* TAR_OPTIONS, environment variable: using tar options. (line 30)
-* TAR_REALNAME, to-command environment: Writing to an External Program.
- (line 40)
-* TAR_SIZE, to-command environment: Writing to an External Program.
- (line 61)
-* TAR_SUBCOMMAND, checkpoint script environment: checkpoints. (line 117)
-* TAR_SUBCOMMAND, info script environment variable: Multi-Volume Archives.
- (line 109)
-* TAR_UID, to-command environment: Writing to an External Program.
- (line 64)
-* TAR_UNAME, to-command environment: Writing to an External Program.
- (line 43)
-* TAR_VERSION, checkpoint script environment: checkpoints. (line 105)
-* TAR_VERSION, info script environment variable: Multi-Volume Archives.
- (line 97)
-* TAR_VOLUME, info script environment variable: Multi-Volume Archives.
- (line 106)
-* tarcat: Tarcat. (line 6)
-* this in date strings: Relative items in date strings.
- (line 33)
-* time of day item: Time of day items. (line 6)
-* time zone correction: Time of day items. (line 30)
-* time zone item <1>: Time zone items. (line 6)
-* time zone item: General date syntax. (line 44)
-* today in date strings: Relative items in date strings.
- (line 33)
-* tomorrow in date strings: Relative items in date strings.
- (line 29)
-* ttyout, checkpoint action: checkpoints. (line 70)
-* TZ: Specifying time zone rules.
- (line 6)
-* Ultrix 3.1 and write failure: Remote Tape Server. (line 40)
-* unpacking: Definitions. (line 22)
-* Updating an archive: update. (line 8)
-* usage-indent: Configuring Help Summary.
- (line 154)
-* Using encrypted archives: gzip. (line 158)
-* ustar archive format: ustar. (line 6)
-* uuencode: Applications. (line 8)
-* v7 archive format: old. (line 6)
-* VCS, excluding files: exclude. (line 39)
-* Verbose operation: verbose. (line 18)
-* Verifying a write operation: verify. (line 6)
-* Verifying the currency of an archive: compare. (line 6)
-* version control system, excluding files: exclude. (line 39)
-* Version of the tar program: help. (line 6)
-* version-control Emacs variable: backup. (line 49)
-* VERSION_CONTROL: backup. (line 41)
-* volno file: Multi-Volume Archives.
- (line 71)
-* VOLNO_FILE: General-Purpose Variables.
- (line 82)
-* Volume label, listing: label. (line 29)
-* Volume number file: Multi-Volume Archives.
- (line 71)
-* week in date strings: Relative items in date strings.
- (line 15)
-* Where is the archive?: file. (line 8)
-* Working directory, specifying: directory. (line 6)
-* Writing extracted files to standard output: Writing to Standard Output.
- (line 6)
-* Writing new archives: file. (line 36)
-* XLIST: General-Purpose Variables.
- (line 87)
-* xsparse: Sparse Recovery. (line 13)
-* year in date strings: Relative items in date strings.
- (line 15)
-* yesterday in date strings: Relative items in date strings.
- (line 29)
-
+* xform, summary: Option Summary. (line 796)
+* xz: gzip. (line 96)
+* xz, summary: Option Summary. (line 869)
projects / debian / tar / blobdiff