gzip is a file format and a software application used for file compression and decompression. The program was created by Jean-Loup Gailly and Mark Adler as a free software replacement for the compress program used in early Unix systems, and intended for use by the GNU Project (the "g" is from "GNU"). Version 0.1 was first publicly released on 31 October 1992, and version 1.0 followed in February 1993.