| PIGZ(1) | General Commands Manual | PIGZ(1) | 
pigz, unpigz —
| pigz | [ -0..9cdFfhiKkLlNnqORrTtz]
      [-11] [-bblocksize] [-Iiterations] [-Mmaxsplits] [-pthreads] [-Ssuffix] [file ...] | 
| unpigz | [ -cfhiKkLlNnqRrTtz] [-bblocksize] [-pthreads] [-Ssuffix] [file ...] | 
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(3)), 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.
-#,
    --fast,
    - -best-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-c,
    --stdout,
    - -to-stdout-d,
    --decompress,
    --uncompress-F,
    --first-f,
    --force-h,
    --help-I,
    --iterations
    n-i,
    --independent-K,
    --zip-k,
    --keep-L,
    --licensepigz license and quit.-l,
    --list-M,
    --maxsplits
    n-N,
    --name-n,
    --no-name-O,
    --oneblock-p,
    --processes
    n-q,
    --quiet,
    - -silent-R,
    --rsyncable-r,
    --recursive-S,
    --suffix
    .sss-T,
    --no-time-t,
    --test-V,
    --version-v,
    --verbose-z,
    --zlibCopyright (C) 2007, 2008, 2009, 2010 Mark Adler <madler@alumni.caltech.edu>
| June 15, 2014 | NetBSD 10.1 |