Ubuntu Manpage: pbzip2 - parallel bzip2 file compressor, v1.1.9

name
synopsis
description
options
file sizes
examples
see also
author

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.

AUTHOR

       Jeff Gilchrist

       http://compression.ca

                                                                                                       pbzip2(1)