.\" $NetBSD: gzip.1,v 1.21 2011/06/19 02:22:36 christos Exp $ .\" .\" Copyright (c) 1997, 2003, 2004 Matthew R. Green .\" All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR .\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES .\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. .\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, .\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, .\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; .\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED .\" AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, .\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" $FreeBSD: src/usr.bin/gzip/gzip.1,v 1.11 2011/10/10 06:37:32 delphij Exp $ .Dd October 9, 2011 .Dt GZIP 1 .Os .Sh NAME .Nm gzip .Nd compression/decompression tool using Lempel-Ziv coding (LZ77) .Sh SYNOPSIS .Nm .Op Fl cdfhkLlNnqrtVv .Op Fl S Ar suffix .Ar file .Oo .Ar file Oo ... .Oc .Oc .Nm gunzip .Op Fl cfhkLNqrtVv .Op Fl S Ar suffix .Ar file .Oo .Ar file Oo ... .Oc .Oc .Nm zcat .Op Fl fhV .Ar file .Oo .Ar file Oo ... .Oc .Oc .Sh DESCRIPTION The .Nm program compresses and decompresses files using Lempel-Ziv coding (LZ77). If no .Ar files are specified, .Nm will compress from standard input, or decompress to standard output. When in compression mode, each .Ar file will be replaced with another file with the suffix, set by the .Fl S Ar suffix option, added, if possible. .Pp In decompression mode, each .Ar file will be checked for existence, as will the file with the suffix added. Each .Ar file argument must contain a separate complete archive; when multiple .Ar files are indicated, each is decompressed in turn. .Pp In the case of .Nm gzcat the resulting data is then concatenated in the manner of .Xr cat 1 . .Pp If invoked as .Nm gunzip then the .Fl d option is enabled. If invoked as .Nm zcat or .Nm gzcat then both the .Fl c and .Fl d options are enabled. When invoked as .Nm zcat , .Dq .Z will be appended to all filenames that do not have that suffix. .Pp This version of .Nm is also capable of decompressing files compressed using .Xr compress 1 or .Xr bzip2 1 . .Sh OPTIONS The following options are available: .Bl -tag -width XXrXXXrecursiveX .It Fl 1 , -fast .It Fl 2 , 3 , 4 , 5 , 6 , 7 , 8 .It Fl 9 , -best These options change the compression level used, with the .Fl 1 option being the fastest, with less compression, and the .Fl 9 option being the slowest, with optimal compression. The default compression level is 6. .It Fl c , -stdout , -to-stdout This option specifies that output will go to the standard output stream, leaving files intact. .It Fl d , -decompress , -uncompress This option selects decompression rather than compression. .It Fl 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 .Fl c option, allowing non-compressed data to pass through unchanged. .It Fl h , -help This option prints a usage summary and exits. .It Fl k , -keep Keep (don't delete) input files during compression or decompression. .It Fl L , -license This option prints .Nm license. .It Fl l , -list This option displays information about the file's compressed and uncompressed size, ratio, uncompressed name. With the .Fl v option, it also displays the compression method, CRC, date and time embedded in the file. .It Fl N , -name This option causes the stored filename in the input file to be used as the output file. .It Fl n , -no-name This option stops the filename and timestamp from being stored in the output file. .It Fl q , -quiet With this option, no warnings or errors are printed. .It Fl r , -recursive This option is used to .Nm the files in a directory tree individually, using the .Xr fts 3 library. .It Fl S Ar suffix , Fl -suffix Ar suffix This option changes the default suffix from .gz to .Ar suffix . .It Fl t , -test This option will test compressed files for integrity. .It Fl V , -version This option prints the version of the .Nm program. .It Fl v , -verbose This option turns on verbose mode, which prints the compression ratio for each file compressed. .El .Sh ENVIRONMENT If the environment variable .Ev 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 .Ev GZIP . .Sh SEE ALSO .Xr bzip2 1 , .Xr compress 1 , .Xr xz 1 , .Xr fts 3 , .Xr zlib 3 , .Xr compat 5 .Sh HISTORY The .Nm 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 .Nm program for .Nx 2.0 . .Pp This implementation of .Nm was ported based on the .Nx .Nm , and first appeared in .Fx 7.0 . .Sh AUTHORS .An -nosplit This implementation of .Nm was written by .An Matthew R. Green Aq mrg@eterna.com.au with unpack support written by .An Xin LI Aq delphij@FreeBSD.org . .Sh BUGS According to RFC 1952, the recorded file size is stored in a 32-bit integer, therefore, it can not represent files larger than 4GB. This limitation also applies to .Fl l option of .Nm utility.