Skip site navigation (1)Skip section navigation (2)

FreeBSD Man Pages

Man Page or Keyword Search:
Man Architecture
Apropos Keyword Search (all sections) Output format
home | help
GZIP(1)			FreeBSD	General	Commands Manual		       GZIP(1)

NAME
     gzip -- compression/decompression tool using Lempel-Ziv coding (LZ77)

SYNOPSIS
     gzip [-cdfhkLlNnqrtVv] [-S	suffix]	file [file [...]]
     gunzip [-cfhkLNqrtVv] [-S suffix] file [file [...]]
     zcat [-fhV] file [file [...]]

DESCRIPTION
     The gzip program compresses and decompresses files	using Lempel-Ziv cod-
     ing (LZ77).  If no	files are specified, gzip will compress	from standard
     input, or decompress to standard output.  When in compression mode, each
     file will be replaced with	another	file with the suffix, set by the -S
     suffix option, added, if possible.

     In	decompression mode, each file will be checked for existence, as	will
     the file with the suffix added.  Each file	argument must contain a	sepa-
     rate complete archive; when multiple files	are indicated, each is decom-
     pressed in	turn.

     In	the case of gzcat the resulting	data is	then concatenated in the man-
     ner of cat(1).

     If	invoked	as gunzip then the -d option is	enabled.  If invoked as	zcat
     or	gzcat then both	the -c and -d options are enabled.

     This version of gzip is also capable of decompressing files compressed
     using compress(1) or bzip2(1).

OPTIONS
     The following options are available:

     -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 com-
		       pression.  The default compression level	is 6.

     -c, --stdout, --to-stdout
		       This option specifies that output will go to the	stan-
		       dard output stream, leaving files intact.

     -d, --decompress, --uncompress
		       This option selects decompression rather	than compres-
		       sion.

     -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 (don't delete) input files during compression or
		       decompression.

     -L, --license     This option prints gzip license.

     -l, --list	       This option displays information	about the file's com-
		       pressed and uncompressed	size, ratio, uncompressed
		       name.  With the -v option, it also displays the com-
		       pression	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.

ENVIRONMENT
     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.

SEE ALSO
     bzip2(1), compress(1), fts(3), zlib(3)

HISTORY
     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 NetBSD	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 NetBSD 2.0.

     This implementation of gzip was ported based on the NetBSD	gzip, and
     first appeared in FreeBSD 7.0.

AUTHORS
     This implementation of gzip was written by	Matthew	R. Green
     <mrg@eterna.com.au> with unpack support written by	Xin LI
     <delphij@FreeBSD.org>.

BUGS
     According to RFC 1952, the	recorded file size is stored in	a 32-bit inte-
     ger, therefore, it	can not	represent files	larger than 4GB.  This limita-
     tion also applies to -l option of gzip utility.

FreeBSD	10.1			 May 23, 2011			  FreeBSD 10.1

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | ENVIRONMENT | SEE ALSO | HISTORY | AUTHORS | BUGS

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=zcat&sektion=1&manpath=FreeBSD+9.3-RELEASE>

home | help