pbzip2(1)

NAME

   pbzip2  -  parallel bzip2 file compressor, v1.1.9

SYNOPSIS

   pbzip2 [ -123456789 ] [ -b#cdfhklm#p#qrS#tvVz ] [ filenames ...  ]

DESCRIPTION

   pbzip2  is  a  parallel  implementation of the bzip2 block-sorting file
   compressor that uses pthreads and achieves near-linear speedup  on  SMP
   machines.  The  output  of  this version is fully compatible with bzip2
   v1.0.2  or  newer  (ie:  anything  compressed  with   pbzip2   can   be
   decompressed with bzip2).

   pbzip2  should  work  on  any system that has a pthreads compatible C++
   compiler (such as gcc). It has been tested on: Linux, Windows (cygwin),
   Solaris, Tru64/OSF1, HP-UX, and Irix.

   The  default settings for pbzip2 will work well in most cases. The only
   switch you will likely need to use is -d to decompress files and -p  to
   set  the  #  of  processors  for  pbzip2  to  use  if autodetect is not
   supported on your system, or you want to use a specific # of CPUs.

OPTIONS

   -b#    Where # is block size in 100k steps (default 9 = 900k)

   -c, --stdout
          Output to standard out (stdout)

   -d,--decompress
          Decompress file

   -f,--force
          Force, overwrite existing output file

   -h,--help
          Print this help message

   -k,--keep
          Keep input file, do not delete

   -l,--loadavg
          Load average determines max number processors to use

   -m#    Where # is max memory usage in 1MB steps (default 100 = 100MB)

   -p#    Where # is the number of processors (default: autodetect)

   -q,--quiet
          Quiet mode (default)

   -r,--read
          Read entire input file into RAM and split between processors

   -S#    Child thread stack size in 1KB  steps  (default  stack  size  if
          unspecified)

   -t,--test
          Test compressed file integrity

   -v,--verbose
          Verbose mode

   -V     Display version info for pbzip2 then exit

   -z,--compress
          Compress file (default)

   -1,--fast ... -9,--best
          Set BWT block size to 100k .. 900k (default 900k).

   --ignore-trailing-garbage=#
          Ignore trailing garbage flag (1 - ignored; 0 - forbidden)

   If  no  file  names  are  given, pbzip2 compresses or decompresses from
   standard input to standard output.

FILE SIZES

   You should be able to compress files larger than 4GB with pbzip2.

   Files that are compressed with pbzip2 are broken  up  into  pieces  and
   each individual piece is compressed.  This is how pbzip2 runs faster on
   multiple CPUs since the pieces can be compressed  simultaneously.   The
   final  .bz2  file may be slightly larger than if it was compressed with
   the regular bzip2 program due to this file splitting (usually less than
   0.2%  larger).   Files  that  are compressed with pbzip2 will also gain
   considerable speedup when decompressed using pbzip2.

   Files that were compressed using bzip2 will not see speedup since bzip2
   packages  the  data  into  a  single chunk that cannot be split between
   processors.

EXAMPLES

   Example 1: pbzip2 myfile.tar

   This example will compress the file "myfile.tar"  into  the  compressed
   file "myfile.tar.bz2". It will use the autodetected # of processors (or
   2 processors if autodetect not supported) with the default  file  block
   size of 900k and default BWT block size of 900k.

   Example 2: pbzip2 -b15k myfile.tar

   This  example  will  compress the file "myfile.tar" into the compressed
   file "myfile.tar.bz2". It will use the autodetected # of processors (or
   2  processors  if  autodetect  not supported) with a file block size of
   1500k and a BWT block size of 900k. The file "myfile.tar" will  not  be
   deleted after compression is finished.

   Example 3: pbzip2 -p4 -r -5 myfile.tar second*.txt

   This  example  will  compress the file "myfile.tar" into the compressed
   file "myfile.tar.bz2". It will use 4 processors with a BWT  block  size
   of  500k.  The file block size will be the size of "myfile.tar" divided
   by 4 (# of processors) so that the data will be split evenly among each
   processor.   This  requires  you have enough RAM for pbzip2 to read the
   entire file into memory for compression. Pbzip2 will then use the  same
   options   to   compress   all  other  files  that  match  the  wildcard
   "second*.txt" in that directory.

   Example   4:   tar   cf    myfile.tar.bz2    --use-compress-prog=pbzip2
   dir_to_compress/
   Example 4: tar -c directory_to_compress/ | pbzip2 -c > myfile.tar.bz2

   These  examples  will  compress the data being given to pbzip2 via pipe
   from TAR into the compressed file "myfile.tar.bz2".  It  will  use  the
   autodetected  #  of  processors  (or  2  processors  if  autodetect not
   supported) with the default file block size of  900k  and  default  BWT
   block  size  of  900k.   TAR  is  collecting  all of the files from the
   "directory_to_compress/" directory and passing the data to pbzip2 as it
   works.

   Example 5: pbzip2 -d -m500 myfile.tar.bz2

   This  example  will  decompress  the  file  "myfile.tar.bz2"  into  the
   decompressed file "myfile.tar". It  will  use  the  autodetected  #  of
   processors (or 2 processors if autodetect not supported). It will use a
   maximum of 500MB of memory for decompression.  The switches -b, -r, and
   -1..-9 are not valid for decompression.

   Example 6: pbzip2 -dc myfile.tar.bz2 | tar x

   This example will decompress and untar the file "myfile.tar.bz2" piping
   the output of the decompressing pbzip2 to tar.

   Example 7: pbzip2 -c < myfile.txt > myfile.txt.bz2

   This example will read myfile.txt from standard input compressing it to
   standard output which is redirected to to myfile.txt.bz2.

SEE ALSO

   bzip2(1) gzip(1) lzip(1) rzip(1) zip(1)

AUTHOR

   Jeff Gilchrist

   http://compression.ca

                                                                 pbzip2(1)

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Free and Open Source Software