glenda.party
term% ls -F
term% pwd
$home/manuals/9front/1/gzip
term% cat index.txt
GZIP(1)                     General Commands Manual                    GZIP(1)



NAME
       gzip,  gunzip,  bzip2, bunzip2, compress, uncompress, zip, unzip - com‐
       press and expand data

SYNOPSIS
       gzip [-cvD[1-9]] [file ...]

       gunzip [-ctTvD] [file ...]

       bzip2 [-cvD[1-9]] [file ...]

       bunzip2 [-cvD] [file ...]

       compress [ -cv ] [ file ...  ]

       uncompress [ -cv ] [ file ...  ]

       zip [-avD[1-9]] [-f zipfile] file [...]

       unzip [-cistTvD] [-f zipfile] [file ...]

DESCRIPTION
       Gzip encodes files with a hybrid Lempel-Ziv 1977 and  Huffman  compres‐
       sion  algorithm known as deflate.  Most of the time, the resulting file
       is smaller, and will never be much bigger.  Output files are  named  by
       taking  the  last path element of each file argument and appending .gz;
       if the resulting name ends with .tar.gz, it is converted  to  .tgz  in‐
       stead.   Gunzip  reverses  the  process.  Its output files are named by
       taking the last path element of each file argument, converting .tgz  to
       .tar.gz,  and  stripping  any .gz; the resulting name must be different
       from the original name.

       Bzip2 and bunzip2 are similar in interface to gzip and gunzip, but  use
       a  modified  Burrows-Wheeler  block sorting compression algorithm.  The
       default suffix for output files is .bz2, with .tar.bz2  becoming  .tbz.
       Bunzip2 recognizes the extension .tbz2 as a synonym for .tbz.

       Compress  and  uncompress  are similar in interface to gzip and gunzip,
       but use the Lempel-Ziv-Welch compression algorithm.  The default suffix
       for  output files is .Z.  Compress is one of the oldest widespread Unix
       compression programs.

       Zip encodes the named files and places the  results  into  the  archive
       zipfile,  or  the  standard output if no file is given.  Unzip extracts
       files from an archive created by zip.  If no files are named  as  argu‐
       ments,  all  of files in the archive are extracted.  A directory's name
       implies all recursively contained files and subdirectories.  Zip is the
       de facto standard for compression on Microsoft operating systems.

       None  of  these  programs  removes  the original files.  If the process
       fails, the faulty output files are removed.

       The options are:

       -a    Automaticialy creates directories as needed, needed for zip files
             created by broken implementations which omit directories.

       -c    Write to standard output rather than creating an output file.

       -i    Convert all archive file names to lower case.

       -s    Streaming  mode.   Looks  at  the file data adjacent to each com‐
             pressed file rather than seeking in the central  file  directory.
             This is the mode used by unzip if no zipfile is specified.  If -s
             is given, -T is ignored.

       -t    List matching files in the archive rather than extracting them.

       -T    Set the output time to that specified in the archive.

       -1 .. -9
             Sets the compression level.  -1 is tuned for speed, -9 for  mini‐
             mal output size.  The best compromise is -6, the default.

       -v    Produce  more descriptive output.  With -t, adds the uncompressed
             size in bytes and the modification time to the  output.   Without
             -t,  prints the names of files on standard error as they are com‐
             pressed or decompressed.

       -D    Produce debugging output.

SOURCE
       /sys/src/cmd/gzip
       /sys/src/cmd/bzip2
       /sys/src/cmd/compress

SEE ALSO
       tar(1)
       "A Technique for High Performance Data Compression",  Terry  A.  Welch,
       IEEE Computer, vol. 17, no. 6 (June 1984), pp. 8-19.

BUGS
       Unzip  can only extract files which are uncompressed or compressed with
       the deflate compression scheme.  Recent zip files fall into this  cate‐
       gory.   Very  recent  zip  files may have tables of contents that unzip
       cannot read.  Such files are still readable by invoking unzip with  the
       -s option.



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