1pbzip2(1)                   General Commands Manual                  pbzip2(1)
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NAME

6       pbzip2  -  parallel bzip2 file compressor, v1.0.2
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SYNOPSIS

9       pbzip2 [ -123456789 ] [ -b#cdfklp#rtvV ] [ filenames ...  ]
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DESCRIPTION

12       pbzip2  is  a  parallel  implementation of the bzip2 block-sorting file
13       compressor that uses pthreads and achieves near-linear speedup  on  SMP
14       machines.  The  output  of  this version is fully compatible with bzip2
15       v1.0.2 or newer (ie: anything compressed  with  pbzip2  can  be  decom‐
16       pressed with bzip2).
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18       pbzip2  should  work  on  any system that has a pthreads compatible C++
19       compiler (such as gcc). It has been tested on: Linux, Windows (cygwin),
20       Solaris, Tru64/OSF1, HP-UX, and Irix.
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22       The  default settings for pbzip2 will work well in most cases. The only
23       switch you will likely need to use is -d to decompress files and -p  to
24       set  the  #  of  processors for pbzip2 to use if autodetect is not sup‐
25       ported on your system, or you want to use a specific # of CPUs.
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OPTIONS

28       -b#    Where # is the file block size in 100k (default 9 = 900k)
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30       -c     Output to standard out (stdout)
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32       -d     Decompress file
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34       -f     Force, overwrite existing output file
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36       -k     Keep input file, do not delete
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38       -l     Load average determines max number processors to use
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40       -p#    Where # is the number of processors (default: autodetect)
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42       -r     Read entire input file into RAM and split between processors
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44       -t     Test compressed file integrity
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46       -v     Verbose mode
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48       -V     Display version info for pbzip2 then exit
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50       -1..9  Set BWT block size to 100k .. 900k (default 900k)
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FILE SIZES

53       You should be able to compress files larger than 4GB with pbzip2.
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55       Files that are compressed with pbzip2 are broken  up  into  pieces  and
56       each individual piece is compressed.  This is how pbzip2 runs faster on
57       multiple CPUs since the pieces can be compressed  simultaneously.   The
58       final  .bz2  file may be slightly larger than if it was compressed with
59       the regular bzip2 program due to this file splitting (usually less than
60       0.2%  larger).   Files  that  are compressed with pbzip2 will also gain
61       considerable speedup when decompressed using pbzip2.
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63       Files that were compressed using bzip2 will not see speedup since bzip2
64       packages the data into a single chunk that cannot be split between pro‐
65       cessors.  If you have a large file that was  created  with  bzip2  (say
66       1.5GB  for  example) you will likely not be able to decompress the file
67       with pbzip2 since pbzip2 will try to allocate 1.5GB of memory to decom‐
68       press  it, and that call might fail depending on your system resources.
69       If the same 1.5GB file had of been compressed  with  pbzip2,  it  would
70       decompress  fine  with  pbzip2.  If you are unable to decompress a file
71       with pbzip2 due to its size, use the regular bzip2 instead.
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EXAMPLES

74       Example 1: pbzip2 myfile.tar
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76       This example will compress the file "myfile.tar"  into  the  compressed
77       file "myfile.tar.bz2". It will use the autodetected # of processors (or
78       2 processors if autodetect not supported) with the default  file  block
79       size of 900k and default BWT block size of 900k.
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81       Example 2: pbzip2 -b15k myfile.tar
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83       This  example  will  compress the file "myfile.tar" into the compressed
84       file "myfile.tar.bz2". It will use the autodetected # of processors (or
85       2  processors  if  autodetect  not supported) with a file block size of
86       1500k and a BWT block size of 900k. The file "myfile.tar" will  not  be
87       deleted after compression is finished.
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89       Example 3: pbzip2 -p4 -r -5 myfile.tar second*.txt
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91       This  example  will  compress the file "myfile.tar" into the compressed
92       file "myfile.tar.bz2". It will use 4 processors with a BWT  block  size
93       of  500k.  The file block size will be the size of "myfile.tar" divided
94       by 4 (# of processors) so that the data will be split evenly among each
95       processor.   This  requires  you have enough RAM for pbzip2 to read the
96       entire file into memory for compression. Pbzip2 will then use the  same
97       options  to  compress  all  other  files  that match the wildcard "sec‐
98       ond*.txt" in that directory.
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100       Example 4: pbzip2 -d myfile.tar.bz2
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102       This example will decompress the file "myfile.tar.bz2" into the  decom‐
103       pressed file "myfile.tar". It will use the autodetected # of processors
104       (or 2 processors if autodetect not supported). The switches -b, -r, and
105       -1..-9 are not valid for decompression.
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SEE ALSO

108       bzip2(1)
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AUTHOR

111       Jeff Gilchrist
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113       http://compression.ca
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117                                                                     pbzip2(1)
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