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
+ 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:
- 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.
+ #! /bin/sh
+ export PATH=/usr/bin
+ exec gzip -9 "$@"
+
+ On VMS, the name of the obsolescent environment variable is GZIP_OPT,
+ to avoid a conflict with the symbol set for invocation of the program.
1mSEE ALSO0m
znew(1), zcmp(1), zmore(1), zforce(1), gzexe(1), zip(1), unzip(1), com-
press the file with gzip, which compresses better and uses less
memory.
- 4mfile24m: already has .gz suffix -- no change
+ 4mfile24m: already has .gz suffix -- unchanged
The file is assumed to be already compressed. Rename the file
and try again.
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.)
+ 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
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, 2015-2016 Free Software Foun-
+ dation, Inc.
Copyright (C) 1992, 1993 Jean-loup Gailly
Permission is granted to make and distribute verbatim copies of this