-.PU
.TH GZIP 1 local
.SH NAME
gzip, gunzip, zcat \- compress or expand files
.I zip
can be uncompressed by gzip only if they have a single member compressed
with the 'deflation' method. This feature is only intended to help
-conversion of tar.zip files to the tar.gz format. To extract zip files
+conversion of tar.zip files to the tar.gz format. To extract a
+.I zip
+file with a single member, use a command like
+.I "gunzip <foo.zip"
+or
+.IR "gunzip -S .zip foo.zip" .
+To extract zip files
with several members, use
.I unzip
instead of
Typically, text such as source code or English
is reduced by 60\-70%.
Compression is generally much better than that achieved by
-LZW (as used in
+LZW (as used in
.IR compress ),
Huffman coding (as used in
.IR pack ),
.I gzip
preserves the mode, ownership and timestamps of files when compressing
or decompressing.
+.PP
+The
+.I gzip
+file format is specified in P. Deutsch, \s-1GZIP\s0 file format
+specification version 4.3, <ftp://ftp.isi.edu/in-notes/rfc1952.txt>,
+Internet RFC 1952 (May 1996). The
+.I zip
+deflation format is specified in P. Deutsch, \s-1DEFLATE\s0 Compressed
+Data Format Specification version 1.3,
+<ftp://ftp.isi.edu/in-notes/rfc1951.txt>, Internet RFC 1951 (May 1996).
.SH OPTIONS
.TP
.TP
.B \-r --recursive
Travel the directory structure recursively. If any of the file names
-specified on the command line are directories,
+specified on the command line are directories,
.I gzip
will descend into the directory and compress all the files it finds there
(or decompress them in the case of
gzip -c file2 >> foo.gz
Then
+
gunzip -c foo
is equivalent to
.SH "SEE ALSO"
znew(1), zcmp(1), zmore(1), zforce(1), gzexe(1), zip(1), unzip(1), compress(1),
pack(1), compact(1)
+.PP
+The
+.I gzip
+file format is specified in P. Deutsch, \s-1GZIP\s0 file format
+specification version 4.3,
+.BR <ftp://ftp.isi.edu/in-notes/rfc1952.txt> ,
+Internet RFC 1952 (May 1996).
+The
+.I zip
+deflation format is specified in P. Deutsch, \s-1DEFLATE\s0 Compressed
+Data Format Specification version 1.3,
+.BR <ftp://ftp.isi.edu/in-notes/rfc1951.txt> ,
+Internet RFC 1951 (May 1996).
.SH "DIAGNOSTICS"
Exit status is normally 0;
if an error occurs, exit status is 1. If a warning occurs, exit status is 2.
-.PP
+.TP
Usage: gzip [-cdfhlLnNrtvV19] [-S suffix] [file ...]
-.in +8
Invalid options were specified on the command line.
-.in -8
-.IR file :
-not in gzip format
-.in +8
+.TP
+\fIfile\fP\^: not in gzip format
The file specified to
.I gunzip
has not been compressed.
-.in -8
-.IR file:
-Corrupt input. Use zcat to recover some data.
-.in +8
+.TP
+\fIfile\fP\^: Corrupt input. Use zcat to recover some data.
The compressed file has been damaged. The data up to the point of failure
can be recovered using
-.in +8
-zcat file > recover
-.in -16
-.IR file :
-compressed with
-.I xx
-bits, can only handle
-.I yy
-bits
-.in +8
+
+ zcat \fIfile\fP > recover
+.TP
+\fIfile\fP\^: compressed with \fIxx\fP bits, can only handle \fIyy\fP bits
.I File
was compressed (using LZW) by a program that could deal with
-more
+more
.I bits
than the decompress code on this machine.
Recompress the file with gzip, which compresses better and uses
less memory.
-.in -8
-.IR file :
-already has .gz suffix -- no change
-.in +8
+.TP
+\fIfile\fP\^: already has .gz suffix -- no change
The file is assumed to be already compressed.
Rename the file and try again.
-.in -8
-.I file
-already exists; do you wish to overwrite (y or n)?
-.in +8
+.TP
+\fIfile\fP already exists; do you wish to overwrite (y or n)?
Respond "y" if you want the output file to be replaced; "n" if not.
-.in -8
+.TP
gunzip: corrupt input
-.in +8
A SIGSEGV violation was detected which usually means that the input file has
been corrupted.
-.in -8
-.I "xx.x%"
-.in +8
-Percentage of the input saved by compression.
+.TP
+\fIxx.x%\fP Percentage of the input saved by compression.
(Relevant only for
.BR \-v
and
.BR \-l \.)
-.in -8
+.TP
-- not a regular file or directory: ignored
-.in +8
When the input file is not a regular file or directory,
(e.g. a symbolic link, socket, FIFO, device file), it is
left unaltered.
-.in -8
--- has
-.I xx
-other links: unchanged
-.in +8
+.TP
+-- has \fIxx\fP other links: unchanged
The input file has links; it is left unchanged. See
.IR ln "(1)"
for more information. Use the
.B \-f
flag to force compression of multiply-linked files.
-.in -8
.SH CAVEATS
When writing compressed data to a tape, it is generally necessary to
pad the output with zeroes up to a block boundary. When the data is
for reading and writing compressed data on tapes. (This example
assumes you are using the GNU version of tar.)
.SH BUGS
-The --list option reports incorrect sizes if they exceed 2 gigabytes.
+The gzip format represents the the input size modulo 2^32, so the
+--list option reports incorrect uncompressed sizes and compression
+ratios for uncompressed files 4 GB and larger. To work around this
+problem, you can use the following command to discover a large
+uncompressed file's true size:
+
+ zcat file.gz | wc -c
+
The --list option reports sizes as -1 and crc as ffffffff if the
compressed file is on a non seekable media.
.I compress
compresses better than
.I gzip.
+.SH "COPYRIGHT NOTICE"
+Copyright \(co 1998, 1999, 2001, 2002 Free Software Foundation, Inc.
+.br
+Copyright \(co 1992, 1993 Jean-loup Gailly
+.PP
+Permission is granted to make and distribute verbatim copies of
+this manual provided the copyright notice and this permission notice
+are preserved on all copies.
+.ig
+Permission is granted to process this file through troff and print the
+results, provided the printed document carries copying permission
+notice identical to this one except for the removal of this paragraph
+(this paragraph not being relevant to the printed manual).
+..
+.PP
+Permission is granted to copy and distribute modified versions of this
+manual under the conditions for verbatim copying, provided that the entire
+resulting derived work is distributed under the terms of a permission
+notice identical to this one.
+.PP
+Permission is granted to copy and distribute translations of this manual
+into another language, under the above conditions for modified versions,
+except that this permission notice may be stated in a translation approved
+by the Foundation.
\input texinfo @c -*-texinfo-*-
@c %**start of header
@setfilename gzip.info
+@include version.texi
@settitle Gzip User's Manual
@finalout
@setchapternewpage odd
@c %**end of header
-
-@ifinfo
-This file documents the the GNU @code{gzip} command for compressing files.
-
-Copyright (C) 1992-1993 Jean-loup Gailly
-
-Permission is granted to make and distribute verbatim copies of
-this manual provided the copyright notice and this permission notice
-are preserved on all copies.
-
-@ignore
-Permission is granted to process this file through TeX and print the
-results, provided the printed document carries copying permission
-notice identical to this one except for the removal of this paragraph
-(this paragraph not being relevant to the printed manual).
-
-@end ignore
-Permission is granted to copy and distribute modified versions of this
-manual under the conditions for verbatim copying, provided that the entire
-resulting derived work is distributed under the terms of a permission
-notice identical to this one.
-
-Permission is granted to copy and distribute translations of this manual
-into another language, under the above conditions for modified versions,
-except that this permission notice may be stated in a translation approved
-by the Foundation.
-@end ifinfo
+@copying
+This manual is for Gzip
+(version @value{VERSION}, @value{UPDATED}),
+and documents commands for compressing and decompressing data.
+
+Copyright @copyright{} 1998, 1999, 2001, 2002 Free Software
+Foundation, Inc.
+
+Copyright @copyright{} 1992, 1993 Jean-loup Gailly
+
+@quotation
+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.''
+
+(a) The FSF's Back-Cover Text is: ``You have freedom to copy and modify
+this GNU Manual, like GNU software. Copies published by the Free
+Software Foundation raise funds for GNU development.''
+@end quotation
+@end copying
+
+@c Debian install-info (up through at least version 1.9.20) uses only the
+@c first dircategory. Put this one first, as it is more useful in practice.
+@dircategory Individual utilities
+@direntry
+* gzip: (gzip)Invoking gzip. Compress files.
+@end direntry
+
+@dircategory Utilities
+@direntry
+* Gzip: (gzip). The gzip command for compressing files.
+@end direntry
@titlepage
@title gzip
@subtitle The data compression program
-@subtitle Edition 1.2.4, for Gzip Version 1.2.4
-@subtitle July 1993
+@subtitle for Gzip Version @value{VERSION}
+@subtitle @value{UPDATED}
@author by Jean-loup Gailly
@page
@vskip 0pt plus 1filll
-Copyright @copyright{} 1992-1993 Jean-loup Gailly
-
-Permission is granted to make and distribute verbatim copies of
-this manual provided the copyright notice and this permission notice
-are preserved on all copies.
-
-Permission is granted to copy and distribute modified versions of this
-manual under the conditions for verbatim copying, provided that the entire
-resulting derived work is distributed under the terms of a permission
-notice identical to this one.
-
-Permission is granted to copy and distribute translations of this manual
-into another language, under the above conditions for modified versions,
-except that this permission notice may be stated in a translation approved
-by the Foundation.
+@insertcopying
@end titlepage
+@contents
+
+@ifnottex
@node Top, , , (dir)
+@top Compressing Files
-@ifinfo
-This file documents the @code{gzip} command to compress files.
-@end ifinfo
+@insertcopying
+@end ifnottex
@menu
-* Copying:: How you can copy and share @code{gzip}.
* Overview:: Preliminary information.
* Sample:: Sample output from @code{gzip}.
* Invoking gzip:: How to run @code{gzip}.
* Environment:: The @code{GZIP} environment variable
* Tapes:: Using @code{gzip} on tapes.
* Problems:: Reporting bugs.
+* Copying This Manual:: How to make copies of this manual.
* Concept Index:: Index of concepts.
@end menu
-@node Copying, Overview, , Top
-@include gpl.texinfo
-
-@node Overview, Sample, Copying, Top
+@node Overview, Sample, , Top
@chapter Overview
@cindex overview
Files created by @code{zip} can be uncompressed by @code{gzip} only if
they have a single member compressed with the 'deflation' method. This
feature is only intended to help conversion of @code{tar.zip} files to
-the @code{tar.gz} format. To extract @code{zip} files with several
+the @code{tar.gz} format. To extract a @code{zip} file with a single
+member, use a command like @samp{gunzip <foo.zip} or @samp{gunzip -S
+.zip foo.zip}. To extract @code{zip} files with several
members, use @code{unzip} instead of @code{gunzip}.
@code{zcat} is identical to @samp{gunzip -c}. @code{zcat}
disk blocks almost never increases. @code{gzip} preserves the mode,
ownership and timestamps of files when compressing or decompressing.
+The @code{gzip} file format is specified in P. Deutsch, @sc{gzip} file
+format specification version 4.3,
+@uref{ftp://ftp.isi.edu/in-notes/rfc1952.txt, Internet RFC 1952} (May
+1996). The @code{zip} deflation format is specified in P. Deutsch,
+@sc{deflate} Compressed Data Format Specification version 1.3,
+@uref{ftp://ftp.isi.edu/in-notes/rfc1951.txt, Internet RFC 1951} (May
+1996).
+
@node Sample, Invoking gzip, Overview, Top
@chapter Sample Output
@cindex sample
This is the output of the command @samp{gzip -h}:
@example
-gzip 1.2.4 (18 Aug 93)
+gzip 1.3
+(1999-12-21)
usage: gzip [-cdfhlLnNrtvV19] [-S suffix] [file ...]
-c --stdout write on standard output, keep original files unchanged
-d --decompress decompress
-1 --fast compress faster
-9 --best compress better
file... files to (de)compress. If none given, use standard input.
+Report bugs to <bug-gzip@@gnu.org>.
@end example
This is the output of the command @samp{gzip -v texinfo.tex}:
@example
-texinfo.tex: 71.6% -- replaced with texinfo.tex.gz
+texinfo.tex: 69.7% -- replaced with texinfo.tex.gz
@end example
The following command will find all @code{gzip} files in the current
Force compression or decompression even if the file has multiple links
or the corresponding file already exists, or if the compressed data
is read from or written to a terminal. If the input data is not in
-a format recognized by @code{gzip}, and if the option --stdout is also
-given, copy the input data without change to the standard ouput: let
+a format recognized by @code{gzip}, and if the option @samp{--stdout} is also
+given, copy the input data without change to the standard output: let
@code{zcat} behave as @code{cat}. If @samp{-f} is not given, and
when not running in the background, @code{gzip} prompts to verify
whether an existing file should be overwritten.
zcat file.Z | wc -c
@end example
-In combination with the --verbose option, the following fields are also
+In combination with the @samp{--verbose} option, the following fields are also
displayed:
@example
The crc is given as ffffffff for a file not in gzip format.
-With --verbose, the size totals and compression ratio for all files
-is also displayed, unless some sizes are unknown. With --quiet,
+With @samp{--verbose}, the size totals and compression ratio for all files
+is also displayed, unless some sizes are unknown. With @samp{--quiet},
the title and totals lines are not displayed.
+The @code{gzip} format represents the the input size modulo
+@math{2^32}, so the uncompressed size and compression ratio are listed
+incorrectly for uncompressed files 4 GB and larger. To work around
+this problem, you can use the following command to discover a large
+uncompressed file's true size:
+
+@example
+zcat file.gz | wc -c
+@end example
+
@item --license
@itemx -L
Display the @code{gzip} license then quit.
the output with zeroes up to a block boundary. When the data is read and
the whole block is passed to @code{gunzip} for decompression,
@code{gunzip} detects that there is extra trailing garbage after the
-compressed data and emits a warning by default. You have to use the
+compressed data and emits a warning by default if the garbage contains
+nonzero bytes. You have to use the
@samp{--quiet} option to suppress the warning. This option can be set in the
@code{GZIP} environment variable, as in:
tapes. (This example assumes you are using the GNU version of
@code{tar}.)
-@node Problems, Concept Index, Tapes, Top
+@node Problems, Copying This Manual, Tapes, Top
@chapter Reporting Bugs
@cindex bugs
If you find a bug in @code{gzip}, please send electronic mail to
-@w{@samp{jloup@@chorus.fr}} or, if this fails, to
-@w{@samp{bug-gnu-utils@@prep.ai.mit.edu}}. Include the version number,
+@email{bug-gzip@@gnu.org}. Include the version number,
which you can find by running @w{@samp{gzip -V}}. Also include in your
message the hardware and operating system, the compiler used to compile
@code{gzip},
a description of the bug behavior, and the input to @code{gzip} that triggered
the bug.@refill
-@node Concept Index, , Problems, Top
-@unnumbered Concept Index
+@node Copying This Manual, Concept Index, Problems, Top
+@appendix Copying This Manual
+
+@menu
+* GNU Free Documentation License:: License for copying this manual.
+@end menu
+
+@include fdl.texi
+
+@node Concept Index, , Copying This Manual, Top
+@appendix Concept Index
@printindex cp
-@contents
@bye
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