COMPRESS(1)                                           COMPRESS(1)

     NAME
          compress, uncompress, zcat - compress and uncompress files

     SYNOPSIS
          compress [ option ] ...  [ file ] ...

          uncompress [ option ] ... [ file ] ...

          zcat [ file ] ...

     DESCRIPTION
          Compress replaces each file with a compressed verison named
          file.Z.  Modes, dates, and (if possible) owner are pre-
          served.  If no file is specified, the standard input is com-
          pressed onto the standard output.

          Uncompress reverses the operation.

          Zcat uncompresses the files, places the result on the stan-
          dard output, and leaves the files untouched.

          The options are:

          -c   `uncompress -c' means `zcat'.

          -d   `compress -d' means `uncompress'.

          -f   (force) overwrite output file if it exists.

          -F   compress even if output is larger than input.

          -b n use codes up to n bits long; see below.

          -q   (quiet) do not report compression ratios.

          Compress uses the Lempel-Ziv algorithm given in the refer-
          ence.  Common substrings in the file are replaced by 9-bit
          codes, then 10-bit codes, and so on until the -b limit is
          reached.  (The default of 16 can be changed in the source to
          fit a smaller machine.)  If the compression ratio does not
          improve thereafter, compress starts afresh with 9-bit codes.

     DIAGNOSTICS
          The exit status is 1 on error, 2 if the last file did not
          get smaller, 0 otherwise.

     SEE ALSO
          pack(1)
          T. A. Welch, `A Technique for High Performance Data Compres-
          sion,' IEEE Computer , 17 (1984) 8-19.