compress

compress [UNIX] vt.  When used without a qualifier,
   generally refers to {crunch}ing of a file using a particular C
   implementation of compression by James A. Woods et al. and widely
   circulated via {Usenet}; use of {crunch} itself in this sense
   is rare among UNIX hackers.  Specifically, compress is built around
   the Lempel-Ziv-Welch algorithm as described in "A Technique for
   High Performance Data Compression", Terry A. Welch, "IEEE
   Computer", vol. 17, no. 6 (June 1984), pp. 8--19.