NAME

       bzip3 - an efficient statistical file compressor and spiritual successor to bzip2

SYNOPSIS

       bzip3 [ -BbcdehftV ] [ filenames ...  ]

       bz3cat is equivalent to bzip3 -dc

       bunzip3 is equivalent to bzip3 -d

DESCRIPTION

       Compress  or  decompress  a  file  using  run  length  encoding and Lempel Ziv prediction,
       followed by the Burrows-Wheeler transform and arithmetic coding.  bzip3, like its ancestor
       bzip2, excels at compressing text or source code.

       The command-line options are deliberately very similar to those of bzip2, but they are not
       identical.

       bzip3 expects at most two filenames intertwined with flags.  bzip3  will  by  default  not
       overwrite existing files.  If this behaviour is intended, use the -f flag.

       If  no  file  names  are  specified,  bzip3  will compress from standard input to standard
       output, refusing to output binary data to a terminal. The -e flag (encode) is implied.

       bunzip3 (or, bzip3 -d equivalently) decompresses data from standard input to the  standard
       output, refusing to read from a terminal.

       If  two  files  are  specified,  the first one is used in place of standard input, and the
       second one is used in place of standard output.

       If the -c flag is present, bzip3 will read from the specified  file  and  output  data  to
       standard  output instead. Otherwise, if decoding, bzip3 will try to guess the decompressed
       filename by removing the .bz3 extension. If not present, an error  will  be  reported.  If
       encoding,  the  output  filename  will be generated by appending the .bz3 extension to the
       input filename.

OPTIONS

       -B --batch
              Enable batch mode. By default, bzip3 will error if more than two files are  passed,
              and  the two files specified are always treated as input and output. The batch mode
              makes bzip3 treat every file  as  input,  so  for  example  bzip3  -Bd  *.bz3  will
              decompress all .bz3 files in the current directory.

       -b --block N
              Set the block size to N mebibytes. The minimum is 1MiB, the maximum is 511MiB.

       -c --stdout
              Force writing output data to the standard output if one file is specified.

       -d --decode
              Force decompression.

       -e/-z --encode
              Force compression (default behaviour).

       -f --force
              Overwrite existing files.

       -h --help
              Display a help message and exit.

       -j --jobs N
              Set the amount of parallel worker threads that process one block each.

       -k --keep
              Keep   (don't   delete)  the  input  files.  Set  by  default,  provided  only  for
              compatibility with other compressors.

       -v --verbose
              Set verbose output mode to see compression statistics.

       -V --version
              Display version information and exit.

       -t --test
              Verify the validity of compressed blocks.

       --     Treat all subsequent arguments as file names, even if they start with a dash.  This
              is so you can handle files with names beginning with a dash.

FILE FORMAT

       Compression  is  performed  as long as the input block is longer than 64 bytes. Otherwise,
       it's coded as a literal block. In all other cases, the compressed data is written  to  the
       file. The file format has constant overhead of 9 bytes per file and from 9 to 17 bytes per
       block. Random data is coded so that expansion is generally under 0.8%.

       bzip3 uses 32-bit CRC to ensure that the decompressed version of a file  is  identical  to
       the original. This guards against corruption of the compressed data.

MEMORY MANAGEMENT

       The -b flag sets the block size in mebibytes (MiB). The default is 16 MiB. Compression and
       decompression memory usage can be estimated as:

              6 x block size

       Larger block sizes usually give rapidly diminishing returns.   It  is  also  important  to
       appreciate  that  the  decompression  memory requirement is set at compression time by the
       choice of block size.  In general, try and use the largest block size  memory  constraints
       allow, since that maximises the compression achieved.  Compression and decompression speed
       are virtually unaffected by block size.

AUTHOR

       Kamila Szewczyk, kspalaiologos@gmail.com.

       https://github.com/kspalaiologos/bzip3

       Thanks to: Ilya Grebnov,  Benjamin  Strachan,  Caleb  Maclennan,  Ilya  Muravyov,  package
       maintainers  -  Leah Neukirchen, Grigory Kirillov, Maciej Barc, Robert Schutz, Petr Pisar,
       and others. Also everyone who sent patches, helped with portability  problems,  encouraged
       me to work on bzip3 and lent me machines for performance tests.

SEE ALSO

       bzip2(1), bz3less(1), bz3more(1), bz3grep(1), bunzip3(1)