

compress                     Command                     compress




Compress a file

ccoommpprreessss [ -ddffvvcc ] [ -bb_n_u_m ] [ -ww _t_e_m_p_f_i_l_e ] [ _f_i_l_e ... ]

compress compresses a  file using the Lempel-Ziv algorithm.  With
text  files  and  archives, it  often  can  achieve  50% rate  of
compression.

If one or more files  are specified on the command, compress com-
presses them and appends the suffix  .ZZ onto the end of each com-
pressed  file's name.   If no  file is  specified on  the command
line, compress compresses text from the standard input and writes
the compressed text to the standard output.

compress recognizes the following options:

-dd   Decompress rather than compress.

-ff   Force  an output file  to be generated  even if no  space is
     saved by compression.

-vv   Verbose  mode: force compress to  write statistics about its
     performance.

-cc   Send output to stdout.

-bb   The  ``bits'' option.   compress uses the  compression level
     set  via the  num argument.   Previous releases  of compress
     would only allow  values of num up to 12,  with 12 being the
     default value if the  -b option was not specified.  The ver-
     sion of compress  introduced with COHERENT version 3.1 hand-
     les values up to 16, with 12 being the default.

-ww   The  ``workfile'' option.   compress uses workfile  to write
     its  temporary file.   By default  compress uses  RAM device
     /dev/ram1  for temporary  storage.  For  this reason,  it is
     strongly advised  that you not use /dev/ram1  as a RAM disk.
     This  option  may  be  necessary  on machines  with  limited
     amounts of RAM.

If  you  wish to  ensure  backwards  compatibility with  previous
releases  of  COHERENT, do  not  use compress  with  a num  value
greater than 12.

***** See Also *****

commands, ram, uncompress, zcat









COHERENT Lexicon                                           Page 1


