| blob | 28c21b49535cc6fa3ab5b9d3930f2ff8aa4a704b |
1 .\" $NetBSD: gzip.1,v 1.25 2015/04/06 21:41:17 wiz Exp $
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3 .\" Copyright (c) 1997, 2003, 2004 Matthew R. Green
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27 .Dd April 6, 2015
28 .Dt GZIP 1
29 .Os
30 .Sh NAME
31 .Nm gzip
32 .Nd compression/decompression tool using Lempel-Ziv coding (LZ77)
33 .Sh SYNOPSIS
34 .Nm
35 .Op Fl cdfhlNnqrtVv
36 .Op Fl S Ar suffix
37 .Ar file
38 .Oo
39 .Ar file Oo ...
40 .Oc
41 .Oc
42 .Nm gunzip
43 .Op Fl cfhNqrtVv
44 .Op Fl S Ar suffix
45 .Ar file
46 .Oo
47 .Ar file Oo ...
48 .Oc
49 .Oc
50 .Nm zcat
51 .Op Fl fhV
52 .Ar file
53 .Oo
54 .Ar file Oo ...
55 .Oc
56 .Oc
57 .Sh DESCRIPTION
58 The
59 .Nm
60 program compresses and decompresses files using Lempel-Ziv coding
61 (LZ77).
62 If no
63 .Ar files
64 are specified,
65 .Nm
66 will compress from standard input, or decompress to standard output.
67 When in compression mode, each
68 .Ar file
69 will be replaced with another file with the suffix, set by the
70 .Fl S Ar suffix
71 option, added, if possible.
72 In decompression mode, each
73 .Ar file
74 will be checked for existence, as will the file with the suffix
75 added.
76 .Pp
77 If invoked as
78 .Nm gunzip
79 then the
80 .Fl d
81 option is enabled.
82 If invoked as
83 .Nm zcat
84 or
85 .Nm gzcat
86 then both the
87 .Fl c
88 and
89 .Fl d
90 options are enabled.
91 .Pp
92 This version of
93 .Nm
94 is also capable of decompressing files compressed using
95 .Xr compress 1 ,
96 .Xr bzip2 1 ,
97 or
98 .Xr xz 1 .
99 .Sh OPTIONS
100 The following options are available:
101 .Bl -tag -width XXrXXXrecursiveX
102 .It Fl 1 , -fast
103 .It Fl 2
104 .It Fl 3
105 .It Fl 4
106 .It Fl 5
107 .It Fl 6
108 .It Fl 7
109 .It Fl 8
110 .It Fl 9 , -best
111 These options change the compression level used, with the
112 .Fl 1
113 option being the fastest, with less compression, and the
114 .Fl 9
115 option being the slowest, with optimal compression.
116 The default compression level is 6.
117 .It Fl c , -stdout , -to-stdout
118 This option specifies that output will go to the standard output
119 stream, leaving files intact.
120 .It Fl d , -decompress , -uncompress
121 This option selects decompression rather than compression.
122 .It Fl f , -force
123 This option turns on force mode.
124 This allows files with multiple links, overwriting of pre-existing
125 files, reading from or writing to a terminal, and when combined
126 with the
127 .Fl c
128 option, allowing non-compressed data to pass through unchanged.
129 .It Fl h , -help
130 This option prints a usage summary and exits.
131 .It Fl l , -list
132 This option displays information about the file's compressed and
133 uncompressed size, ratio, uncompressed name.
134 With the
135 .Fl v
136 option, it also displays the compression method, CRC, date and time
137 embedded in the file.
138 .It Fl N , -name
139 This option causes the stored filename in the input file to be used
140 as the output file.
141 .It Fl n , -no-name
142 This option stops the filename and timestamp from being stored in
143 the output file.
144 .It Fl q , -quiet
145 With this option, no warnings or errors are printed.
146 .It Fl r , -recursive
147 This option is used to
148 .Nm
149 the files in a directory tree individually, using the
150 .Xr fts 3
151 library.
152 .It Fl S Ar suffix , Fl -suffix Ar suffix
153 This option changes the default suffix from .gz to
154 .Ar suffix .
155 .It Fl t , -test
156 This option will test compressed files for integrity.
157 .It Fl V , -version
158 This option prints the version of the
159 .Nm
160 program.
161 .It Fl v , -verbose
162 This option turns on verbose mode, which prints the compression
163 ratio for each file compressed.
164 .El
165 .Sh ENVIRONMENT
166 If the environment variable
167 .Ev GZIP
168 is set, it is parsed as a white-space separated list of options
169 handled before any options on the command line.
170 Options on the command line will override anything in
171 .Ev GZIP .
172 .Sh SEE ALSO
173 .Xr bzip2 1 ,
174 .Xr compress 1 ,
175 .Xr xz 1 ,
176 .Xr fts 3 ,
177 .Xr zlib 3
178 .Sh HISTORY
179 The
180 .Nm
181 program was originally written by Jean-loup Gailly, licensed under
182 the GNU Public Licence.
183 Matthew R. Green wrote a simple front end for
184 .Nx 1.3
185 distribution media, based on the freely re-distributable zlib library.
186 It was enhanced to be mostly feature-compatible with the original
187 GNU
188 .Nm
189 program for
190 .Nx 2.0 .
191 .Pp
192 This manual documents
193 .Nx
194 .Nm
195 version 20150113.
196 .Sh AUTHORS
197 This implementation of
198 .Nm
199 was written by
200 .An Matthew R. Green Aq Mt mrg@eterna.com.au .