4mGzip24m reduces the size of the named files using Lempel-Ziv coding
(LZ77). Whenever possible, each file is replaced by one with the
extension 1m.gz22m, while keeping the same ownership modes, access and modi-
- fication times. (The default extension is 1m-gz 22mfor VMS, 1mz 22mfor MSDOS,
- OS/2 FAT, Windows NT FAT and Atari.) If no files are specified, or if
- a file name is "-", the standard input is compressed to the standard
- output. 4mGzip24m will only attempt to compress regular files. In particu-
- lar, it will ignore symbolic links.
+ fication times. (The default extension is 1mz 22mfor MSDOS, OS/2 FAT, Win-
+ dows NT FAT and Atari.) If no files are specified, or if a file name
+ is "-", the standard input is compressed to the standard output. 4mGzip0m
+ will only attempt to compress regular files. In particular, it will
+ ignore symbolic links.
If the compressed file name is too long for its file system, 4mgzip24m trun-
cates it. 4mGzip24m attempts to truncate only the parts of the file name
By default, 4mgzip24m keeps the original file name and timestamp in the com-
pressed file. These are used when decompressing the file with the 1m-N0m
option. This is useful when the compressed file name was truncated or
- when the time stamp was not preserved after a file transfer.
+ when the timestamp was not preserved after a file transfer.
Compressed files can be restored to their original form using 4mgzip24m 4m-d0m
or 4mgunzip24m or 4mzcat24m. If the original name saved in the compressed file
method: compression method
crc: the 32-bit CRC of the uncompressed data
- date & time: time stamp for the uncompressed file
+ date & time: timestamp for the uncompressed file
The compression methods currently supported are deflate, com-
press, lzh (SCO compress -H) and pack. The crc is given as
Display the 4mgzip24m license and quit.
1m-n --no-name0m
- When compressing, do not save the original file name and time
+ When compressing, do not save the original file name and time-
stamp by default. (The original name is always saved if the name
had to be truncated.) When decompressing, do not restore the
original file name if present (remove only the 4mgzip24m suffix from
- the compressed file name) and do not restore the original time
+ the compressed file name) and do not restore the original time-
stamp if present (copy it from the compressed file). This option
is the default when decompressing.
1m-N --name0m
- When compressing, always save the original file name and time
+ When compressing, always save the original file name and time-
stamp; this is the default. When decompressing, restore the
- original file name and time stamp if present. This option is
- useful on systems which have a limit on file name length or when
- the time stamp has been lost after a file transfer.
+ original file name and timestamp if present. This option is use-
+ ful on systems which have a limit on file name length or when
+ the timestamp has been lost after a file transfer.
1m-q --quiet0m
Suppress all warnings.
suffixes to try, when deriving an output file name from an input
file name.
+ 1m--synchronous0m
+ Use synchronous output. With this option, 4mgzip24m is less likely
+ to lose data during a system crash, but it can be considerably
+ slower.
+
1m-t --test0m
Test. Check the compressed file integrity.
level is 1m-6 22m(that is, biased towards high compression at expense
of speed).
+ 1m--rsyncable0m
+ When you synchronize a compressed file between two computers,
+ this option allows rsync to transfer only files that were
+ changed in the archive instead of the entire archive. Normally,
+ after a change is made to any file in the archive, the compres-
+ sion algorithm can generate a new version of the archive that
+ does not match the previous version of the archive. In this
+ case, rsync transfers the entire new version of the archive to
+ the remote computer. With this option, rsync can transfer only
+ the changed files as well as a small amount of metadata that is
+ required to update the archive structure in the area that was
+ changed.
+
1mADVANCED USAGE0m
Multiple compressed files can be concatenated. In this case, 4mgunzip0m
will extract all members at once. For example:
ently. gzip is designed as a complement to tar, not as a replacement.
1mENVIRONMENT0m
- The environment variable 1mGZIP 22mcan hold a set of default options for
- 4mgzip24m. These options are interpreted first and can be overwritten by
- explicit command line parameters. For example:
- for sh: GZIP="-8v --name"; export GZIP
- for csh: setenv GZIP "-8v --name"
- for MSDOS: set GZIP=-8v --name
-
- On Vax/VMS, the name of the environment variable is GZIP_OPT, to avoid
- a conflict with the symbol set for invocation of the program.
+ The obsolescent environment variable 1mGZIP 22mcan hold a set of default
+ options for 4mgzip24m. These options are interpreted first and can be over-
+ written by explicit command line parameters. As this can cause prob-
+ lems when using scripts, this feature is supported only for options
+ that are reasonably likely to not cause too much harm, and 4mgzip24m warns
+ if it is used. This feature will be removed in a future release of
+ 4mgzip24m.
+
+ You can use an alias or script instead. For example, if 4mgzip24m is in the
+ directory 1m/usr/bin 22myou can prepend 1m$HOME/bin 22mto your 1mPATH 22mand create an
+ executable script 1m$HOME/bin/gzip 22mcontaining the following:
+
+ #! /bin/sh
+ export PATH=/usr/bin
+ exec gzip -9 "$@"
1mSEE ALSO0m
znew(1), zcmp(1), zmore(1), zforce(1), gzexe(1), zip(1), unzip(1), com-
press(1)
The 4mgzip24m file format is specified in P. Deutsch, GZIP file format spec-
- ification version 4.3, 1m<http://www.ietf.org/rfc/rfc1952.txt>22m, Internet
- RFC 1952 (May 1996). The 4mzip24m deflation format is specified in P.
- Deutsch, DEFLATE Compressed Data Format Specification version 1.3,
- 1m<http://www.ietf.org/rfc/rfc1951.txt>22m, Internet RFC 1951 (May 1996).
+ ification version 4.3, 1m<https://www.ietf.org/rfc/rfc1952.txt>22m, Internet
+ RFC 1952 (May 1996). The 4mzip24m deflation format is specified in P.
+ Deutsch, DEFLATE Compressed Data Format Specification version 1.3,
+ 1m<https://www.ietf.org/rfc/rfc1951.txt>22m, Internet RFC 1951 (May 1996).
1mDIAGNOSTICS0m
- Exit status is normally 0; if an error occurs, exit status is 1. If a
+ Exit status is normally 0; if an error occurs, exit status is 1. If a
warning occurs, exit status is 2.
Usage: gzip [-cdfhklLnNrtvV19] [-S suffix] [file ...]
The file specified to 4mgunzip24m has not been compressed.
4mfile24m: Corrupt input. Use zcat to recover some data.
- The compressed file has been damaged. The data up to the point
+ The compressed file has been damaged. The data up to the point
of failure can be recovered using
zcat 4mfile24m > recover
4mfile24m: compressed with 4mxx24m bits, can only handle 4myy24m bits
- 4mFile24m was compressed (using LZW) by a program that could deal
+ 4mFile24m was compressed (using LZW) by a program that could deal
with more 4mbits24m than the decompress code on this machine. Recom-
- press the file with gzip, which compresses better and uses less
+ press the file with gzip, which compresses better and uses less
memory.
- 4mfile24m: already has .gz suffix -- no change
- The file is assumed to be already compressed. Rename the file
+ 4mfile24m: already has .gz suffix -- unchanged
+ The file is assumed to be already compressed. Rename the file
and try again.
4mfile24m already exists; do you wish to overwrite (y or n)?
- Respond "y" if you want the output file to be replaced; "n" if
+ Respond "y" if you want the output file to be replaced; "n" if
not.
gunzip: corrupt input
- A SIGSEGV violation was detected which usually means that the
+ A SIGSEGV violation was detected which usually means that the
input file has been corrupted.
4mxx.x%24m Percentage of the input saved by compression.
(Relevant only for 1m-v 22mand 1m-l22m.)
-- not a regular file or directory: ignored
- When the input file is not a regular file or directory, (e.g. a
+ When the input file is not a regular file or directory, (e.g. a
symbolic link, socket, FIFO, device file), it is left unaltered.
-- has 4mxx24m other links: unchanged
- The input file has links; it is left unchanged. See 4mln24m(1) for
+ The input file has links; it is left unchanged. See 4mln24m(1) for
more information. Use the 1m-f 22mflag to force compression of multi-
ply-linked files.
1mCAVEATS0m
- 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
- read and the whole block is passed to 4mgunzip24m for decompression, 4mgunzip0m
- detects that there is extra trailing garbage after the compressed data
- and emits a warning by default. You have to use the --quiet option to
- suppress the warning. This option can be set in the 1mGZIP 22menvironment
- variable as in:
- for sh: GZIP="-q" tar -xfz --block-compress /dev/rst0
- for csh: (setenv GZIP -q; tar -xfz --block-compr /dev/rst0
-
- In the above example, gzip is invoked implicitly by the -z option of
- GNU tar. Make sure that the same block size (-b option of tar) is used
- for reading and writing compressed data on tapes. (This example
- assumes you are using the GNU version of tar.)
+ 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
+ read and the whole block is passed to 4mgunzip24m for decompression, 4mgunzip0m
+ detects that there is extra trailing garbage after the compressed data
+ and emits a warning by default. You can use the --quiet option to sup-
+ press the warning.
1mBUGS0m
- The gzip format represents 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
+ The gzip format represents 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 com-
+ The --list option reports sizes as -1 and crc as ffffffff if the com-
pressed file is on a non seekable media.
- In some rare cases, the --best option gives worse compression than the
- default compression level (-6). On some highly redundant files, 4mcom-0m
+ In some rare cases, the --best option gives worse compression than the
+ default compression level (-6). On some highly redundant files, 4mcom-0m
4mpress24m compresses better than 4mgzip24m.
1mCOPYRIGHT NOTICE0m
- Copyright (C) 1998, 1999, 2001, 2002, 2012 Free Software Foundation,
- Inc.
+ Copyright (C) 1998-1999, 2001-2002, 2012, 2015-2018 Free Software Foun-
+ dation, Inc.
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
+ 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 per-
+ 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 per-
mission notice identical to this one.
- Permission is granted to copy and distribute translations of this man-
+ Permission is granted to copy and distribute translations of this man-
ual into another language, under the above conditions for modified ver-
- sions, except that this permission notice may be stated in a transla-
+ sions, except that this permission notice may be stated in a transla-
tion approved by the Foundation.
local GZIP(1)
projects / debian / gzip / blobdiff