3 gzip, gunzip, bzip2, bunzip2, compress, uncompress, zip, unzip \- compress and expand data
57 encodes files with a hybrid Lempel-Ziv 1977 and Huffman compression algorithm
60 Most of the time, the resulting file is smaller,
61 and will never be much bigger.
62 Output files are named by taking the last path element of each file argument
65 if the resulting name ends with
72 Its output files are named by taking the last path element of each file argument,
79 the resulting name must be different from the original name.
84 are similar in interface to
88 but use a modified Burrows-Wheeler block sorting
89 compression algorithm.
90 The default suffix for output files is
97 recognizes the extension
105 are similar in interface to
109 but use the Lempel-Ziv-Welch compression algorithm.
110 The default suffix for output files is
113 is one of the oldest widespread Unix compression programs.
116 encodes the named files and places the results into the archive
118 or the standard output if no file is given.
120 extracts files from an archive created by
122 If no files are named as arguments, all of files in the archive are extracted.
123 A directory's name implies all recursively contained files and subdirectories.
127 standard for compression on Microsoft operating systems.
129 None of these programs removes the original files.
130 If the process fails, the faulty output files are removed.
135 Automaticialy creates directories as needed, needed for zip files
136 created by broken implementations which omit directories.
139 Write to standard output rather than creating an output file.
142 Convert all archive file names to lower case.
145 Streaming mode. Looks at the file data adjacent to each compressed file
146 rather than seeking in the central file directory.
147 This is the mode used by
159 List matching files in the archive rather than extracting them.
162 Set the output time to that specified in the archive.
165 Sets the compression level.
169 for minimal output size.
170 The best compromise is
175 Produce more descriptive output.
178 adds the uncompressed size in bytes and the modification time to the output.
181 prints the names of files on standard error as they are compressed or decompressed.
188 file formats include a modification timestamp which is by default set
189 to the modification time of the files being compressed or the current
190 time when the source file is read from standard input.
193 flag overrides this behaviour and puts a timestamp of zero instead,
194 making the compressed output deterministic.
197 Produce debugging output.
201 .B /sys/src/cmd/bzip2
203 .B /sys/src/cmd/compress
207 "A Technique for High Performance Data Compression",
209 .IR "IEEE Computer" ,
210 vol. 17, no. 6 (June 1984), pp. 8-19.
213 can only extract files which are uncompressed or compressed
216 compression scheme. Recent zip files fall into this category.
217 Very recent zip files may have tables of contents that
219 cannot read. Such files are still readable by invoking