1 .\" $NetBSD: gzip.1,v 1.18 2005/09/30 13:46:56 wiz Exp $
3 .\" Copyright (c) 1997, 2003, 2004 Matthew R. Green
4 .\" All rights reserved.
6 .\" Redistribution and use in source and binary forms, with or without
7 .\" modification, are permitted provided that the following conditions
9 .\" 1. Redistributions of source code must retain the above copyright
10 .\" notice, this list of conditions and the following disclaimer.
11 .\" 2. Redistributions in binary form must reproduce the above copyright
12 .\" notice, this list of conditions and the following disclaimer in the
13 .\" documentation and/or other materials provided with the distribution.
14 .\" 3. The name of the author may not be used to endorse or promote products
15 .\" derived from this software without specific prior written permission.
17 .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 .\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 .\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 .\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 .\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
22 .\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23 .\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
24 .\" AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
25 .\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 .Nd compression/decompression tool using Lempel-Ziv coding (LZ77)
63 program compresses and decompresses files using Lempel-Ziv coding
69 will compress from standard input, or decompress to standard output.
70 When in compression mode, each
72 will be replaced with another file with the suffix, set by the
74 option, added, if possible.
75 In decompression mode, each
77 will be checked for existence, as will the file with the suffix
97 is also capable of decompressing files compressed using
102 The following options are available:
103 .Bl -tag -width XXrXXXrecursiveX
105 .It Fl 2 , 3 , 4 , 5 , 6 , 7 , 8
107 These options change the compression level used, with the
109 option being the fastest, with less compression, and the
111 option being the slowest, with optimal compression.
112 The default compression level is 6.
113 .It Fl c , -stdout , -to-stdout
114 This option specifies that output will go to the standard output
115 stream, leaving files intact.
116 .It Fl d , -decompress , -uncompress
117 This option selects decompression rather than compression.
119 This option turns on force mode.
120 This allows files with multiple links, overwriting of pre-existing
121 files, reading from or writing to a terminal, and when combined
124 option, allowing non-compressed data to pass through unchanged.
126 This option prints a usage summary and exits.
128 Keep (don't delete) input files during compression
135 This option displays information about the file's compressed and
136 uncompressed size, ratio, uncompressed name.
139 option, it also displays the compression method, CRC, date and time
140 embedded in the file.
142 This option causes the stored filename in the input file to be used
145 This option stops the filename from being stored in the output
148 With this option, no warnings or errors are printed.
149 .It Fl r , -recursive
150 This option is used to
152 the files in a directory tree individually, using the
155 .It Fl S Ar suffix , Fl -suffix Ar suffix
156 This option changes the default suffix from .gz to
159 This option will test compressed files for integrity.
161 This option prints the version of the
165 This option turns on verbose mode, which prints the compression
166 ratio for each file compressed.
169 If the environment variable
171 is set, it is parsed as a white-space separated list of options
172 handled before any options on the command line.
173 Options on the command line will override anything in
183 program was originally written by Jean-loup Gailly, licensed under
184 the GNU Public Licence.
185 Matthew R. Green wrote a simple front end for
187 distribution media, based on the freely re-distributable zlib library.
188 It was enhanced to be mostly feature-compatible with the original
194 This implementation of
196 was ported based on the
199 20060927, and first appeared in
202 This implementation of
205 .An Matthew R. Green Aq mrg@eterna.com.au .
207 According to RFC 1952, the recorded file size is stored in a 32-bit
208 integer and therefore it can not represent files that is bigger than
209 4GB in size. This limitation also applies to