NAME

       pigz, unpigz - compress or expand files

SYNOPSIS

       pigz [ -cdfhikKlLnNqrRtTz0..9,11 ] [ -b blocksize ] [ -p threads ] [ -S suffix ] [ name ...  ]
       unpigz [ -cfhikKlLnNqrRtTz ] [ -b blocksize ] [ -p threads ] [ -S suffix ] [ name ...  ]

DESCRIPTION

       Pigz  compresses using threads to make use of multiple processors and cores.  The input is
       broken up into 128 KB chunks with each compressed in parallel.  The individual check value
       for each chunk is also calculated in parallel.  The compressed data is written in order to
       the output, and a combined check value is calculated from the individual check values.

       The compressed data format generated is in the gzip,  zlib,  or  single-entry  zip  format
       using  the  deflate  compression  method.   The  compression  produces partial raw deflate
       streams which are concatenated by a single write thread and wrapped with  the  appropriate
       header and trailer, where the trailer contains the combined check value.

       Each  partial  raw  deflate  stream  is  terminated  by  an  empty stored block (using the
       Z_SYNC_FLUSH option of zlib), in order to end that partial bit stream at a byte  boundary.
       That  allows  the  partial  streams to be concatenated simply as sequences of bytes.  This
       adds a very small four to five byte overhead to the output for each input chunk.

       The default input block size is 128K, but can be changed with the -b option.   The  number
       of  compress  threads  is  set by default to the number of online processors, which can be
       changed using the -p option.  Specifying -p 1 avoids the use of threads entirely.

       The input blocks, while compressed independently, have the last 32K of the previous  block
       loaded  as a preset dictionary to preserve the compression effectiveness of deflating in a
       single thread.  This can be turned off using the -i or --independent option, so  that  the
       blocks can be decompressed independently for partial error recovery or for random access.

       Decompression  can't  be  parallelized,  at  least  not without specially prepared deflate
       streams for that purpose.  As a result, pigz uses a single thread (the  main  thread)  for
       decompression,  but  will  create  three  other  threads  for  reading, writing, and check
       calculation,  which  can  speed  up  decompression  under  some  circumstances.   Parallel
       decompression can be turned off by specifying one process ( -dp 1 or -tp 1 ).

       Compressed files can be restored to their original form using pigz -d or unpigz.

OPTIONS

       -# --fast --best
              Regulate  the  speed of compression using the specified digit #, where -1 or --fast
              indicates the fastest compression  method  (less  compression)  and  -9  or  --best
              indicates the slowest compression method (best compression).  -0 is no compression.
              -11 gives a few percent better compression at a severe cost in execution time.  The
              default is -6.

       -b --blocksize mmm
              Set compression block size to mmmK (default 128KiB).

       -c --stdout --to-stdout
              Write all processed output to stdout (won't delete).

       -d --decompress --uncompress
              Decompress the compressed input.

       -f --force
              Force overwrite, compress .gz, links, and to terminal.

       -h --help
              Display a help screen and quit.

       -i --independent
              Compress blocks independently for damage recovery.

       -k --keep
              Do not delete original file after processing.

       -K --zip
              Compress to PKWare zip (.zip) single entry format.

       -l --list
              List the contents of the compressed input.

       -L --license
              Display the pigz license and quit.

       -n --no-name
              Do not store or restore file name in/from header.

       -N --name
              Store/restore file name and mod time in/from header.

       -p --processes n
              Allow up to n processes (default is the number of online processors)

       -q --quiet --silent
              Print no messages, even on error.

       -r --recursive
              Process the contents of all subdirectories.

       -R --rsyncable
              Input-determined block locations for rsync.

       -S --suffix .sss
              Use suffix .sss instead of .gz (for compression).

       -t --test
              Test the integrity of the compressed input.

       -T --no-time
              Do not store or restore mod time in/from header.

       -v --verbose
              Provide more verbose output.

       -V --version
              Show the version of pigz.

       -z --zlib
              Compress to zlib (.zz) instead of gzip format.

       --     All arguments after "--" are treated as file names (for names that start with "-")

COPYRIGHT NOTICE

       This  software  is provided 'as-is', without any express or implied warranty.  In no event
       will the author be held liable for any damages arising from the use of this software.

       Copyright   (C)   2007,   2008,   2009,   2010,    2011,    2012,    2013    Mark    Adler
       <madler@alumni.caltech.edu>

                                              local                                       PIGZ(1)