PIGZ(1)                              General Commands Manual                              PIGZ(1)

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.
       This also inserts an extra empty block to flag independent blocks by prefacing  each  with
       the nine-byte sequence (in hex): 00 00 FF FF 00 00 00 FF FF.

       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 calcu‐
       lation, 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  indi‐
              cates  the  slowest  compression  method (best compression).  -0 is no compression.
              -11 gives a few percent better compression at a  severe  cost  in  execution  time,
              using the zopfli algorithm by Jyrki Alakuijala.  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. -vV also shows the zlib version.

       -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.

       Copyright (C) 2007-2016 Mark Adler <madler (at) alumni (dot) caltech (dot) edu>

                                         October 1, 2016                                  PIGZ(1)

Usage: pigz [options] [files ...]
  will compress files in place, adding the suffix '.gz'.  If no files are
  specified, stdin will be compressed to stdout.  pigz does what gzip does,
  but spreads the work over multiple processors and cores when compressing.

Options:
  -0 to -9, -11        Compression level (level 11, zopfli, is much slower)
  --fast, --best       Compression levels 1 and 9 respectively
  -b, --blocksize mmm  Set compression block size to mmmK (default 128K)
  -c, --stdout         Write all processed output to stdout (won't delete)
  -d, --decompress     Decompress the compressed input
  -f, --force          Force overwrite, compress .gz, links, and to terminal
  -F  --first          Do iterations first, before block split for -11
  -h, --help           Display a help screen and quit
  -i, --independent    Compress blocks independently for damage recovery
  -I, --iterations n   Number of iterations for -11 optimization
  -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
  -M, --maxsplits n    Maximum number of split blocks for -11
  -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
  -O  --oneblock       Do not split into smaller blocks for -11
  -p, --processes n    Allow up to n compression threads (default is the
                       number of online processors, or 8 if unknown)
  -q, --quiet          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 files