|-1 -, --fast
-2 -, -3 -, -4 -, -5 -, -6 -, -7 -, -8
-9 -, --best
|These options change the compression level used, with the -1 option being the fastest, with less compression, and the -9 option being the slowest, with optimal compression. The default compression level is 6.|
|-c -, --stdout -, --to-stdout|
|This option specifies that output will go to the standard output stream, leaving files intact.|
|-d -, --decompress -, --uncompress|
|This option selects decompression rather than compression.|
|-f -, --force||This option turns on force mode. This allows files with multiple links, symbolic links to regular files, overwriting of pre-existing files, reading from or writing to a terminal, and when combined with the -c option, allowing non-compressed data to pass through unchanged.|
|-h -, --help||This option prints a usage summary and exits.|
|-k -, --keep||Keep (do not delete) input files during compression or decompression.|
|-L -, --license||This option prints gzip license.|
|-l -, --list||This option displays information about the files compressed and uncompressed size, ratio, uncompressed name. With the -v option, it also displays the compression method, CRC, date and time embedded in the file.|
|-N -, --name||This option causes the stored filename in the input file to be used as the output file.|
|-n -, --no-name||This option stops the filename and timestamp from being stored in the output file.|
|-q -, --quiet||With this option, no warnings or errors are printed.|
|-r -, --recursive||This option is used to gzip the files in a directory tree individually, using the fts(3) library.|
|-S suffix,--suffix suffix|
|This option changes the default suffix from .gz to suffix.|
|-t -, --test||This option will test compressed files for integrity.|
|-V -, --version||This option prints the version of the gzip program.|
|-v -, --verbose||This option turns on verbose mode, which prints the compression ratio for each file compressed.|
If the environment variable GZIP is set, it is parsed as a white-space separated list of options handled before any options on the command line. Options on the command line will override anything in GZIP.
The gzip utility exits 0 on success, 1 on errors, and 2 if a warning occurs.
The gzip program was originally written by Jean-loup Gailly, licensed under the GNU Public Licence. Matthew R. Green wrote a simple front end for
.Nx 1.3 distribution media, based on the freely re-distributable zlib library. It was enhanced to be mostly feature-compatible with the original GNU gzip program for
.Nx 2.0 .
This implementation of gzip was ported based on the
.Nx gzip, and first appeared in
.Fx 7.0 .
.An -nosplit This implementation of gzip was written by
.An Matthew R. Green Aq email@example.com with unpack support written by
.An Xin LI Aq delphij@FreeBSD.org .
According to RFC 1952, the recorded file size is stored in a 32-bit integer, therefore, it cannot represent files larger than 4GB. This limitation also applies to -l option of gzip utility.