xenial (1) pigz.1.gz

Provided by: pigz_2.3.1-2_amd64 bug

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 "-")

       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).

       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)