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 PIGZ(1)                                                             PIGZ(1)
                                    local



 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 ).





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      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



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 PIGZ(1)                                                             PIGZ(1)
                                    local



           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 "-")

      These options are unique to the -11 compression level:

      -F --first
           Do iterations first, before block split (default is last).

      -I, --iterations n
           Number of iterations for optimization (default 15).

      -M, --maxsplits n
           Maximum number of split blocks (default 15).

      -O --oneblock
           Do not split into smaller blocks (default is block splitting).

 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.




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 PIGZ(1)                                                             PIGZ(1)
                                    local



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




















































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