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3 .\" Copyright (c) 1997, 2003, 2004 Matthew R. Green
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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.
76 In decompression mode, each
78 will be checked for existence, as will the file with the suffix
82 argument must contain a separate complete archive;
85 are indicated, each is decompressed in turn.
89 the resulting data is then concatenated in the manner of
109 is also capable of decompressing files compressed using
114 The following options are available:
115 .Bl -tag -width XXrXXXrecursiveX
117 .It Fl 2 , 3 , 4 , 5 , 6 , 7 , 8
119 These options change the compression level used, with the
121 option being the fastest, with less compression, and the
123 option being the slowest, with optimal compression.
124 The default compression level is 6.
125 .It Fl c , -stdout , -to-stdout
126 This option specifies that output will go to the standard output
127 stream, leaving files intact.
128 .It Fl d , -decompress , -uncompress
129 This option selects decompression rather than compression.
131 This option turns on force mode.
132 This allows files with multiple links, overwriting of pre-existing
133 files, reading from or writing to a terminal, and when combined
136 option, allowing non-compressed data to pass through unchanged.
138 This option prints a usage summary and exits.
140 Keep (don't delete) input files during compression
147 This option displays information about the file's compressed and
148 uncompressed size, ratio, uncompressed name.
151 option, it also displays the compression method, CRC, date and time
152 embedded in the file.
154 This option causes the stored filename in the input file to be used
157 This option stops the filename from being stored in the output
160 With this option, no warnings or errors are printed.
161 .It Fl r , -recursive
162 This option is used to
164 the files in a directory tree individually, using the
167 .It Fl S Ar suffix , Fl -suffix Ar suffix
168 This option changes the default suffix from .gz to
171 This option will test compressed files for integrity.
173 This option prints the version of the
177 This option turns on verbose mode, which prints the compression
178 ratio for each file compressed.
181 If the environment variable
183 is set, it is parsed as a white-space separated list of options
184 handled before any options on the command line.
185 Options on the command line will override anything in
195 program was originally written by Jean-loup Gailly, licensed under
196 the GNU Public Licence.
197 Matthew R. Green wrote a simple front end for
199 distribution media, based on the freely re-distributable zlib library.
200 It was enhanced to be mostly feature-compatible with the original
206 This implementation of
208 was ported based on the
211 20060927, and first appeared in
214 This implementation of
217 .An Matthew R. Green Aq mrg@eterna.com.au .
219 According to RFC 1952, the recorded file size is stored in a 32-bit
220 integer and therefore it can not represent files that is bigger than
221 4GB in size. This limitation also applies to