[Unix] When used without a qualifier, generally refers to crunching of a file using a particular C implementation of compression by Joseph M. Orost 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.