< tool , compression > GNU compression utility. Gzip reduces the size of the named files using Lempel-Ziv LZ77 compression . Whenever possible, each file is replaced by one with the filename extension ".gz". Compressed files can be restored to their original form using gzip -d or gunzip or zcat.
The Unix " compress " utility is patented (by two separate patents, in fact) and is thus shunned by the GNU Project since it is not free software . They have therefore chosen gzip, which is free of any known software patent s and which tends to compress better anyway. All compressed files in the GNU anonymous FTP area (gnu.org/pub/gnu) are in gzip format and their names end in ".gz" (as opposed to "compress"-compressed files, which end in ".Z").
Gzip can uncompress "compress"-compressed files and "pack" files (which end in ".z"). The decompression algorithms are not patented, only compression is.
The gzip program is available from any GNU archive site in shar , tar , or gzipped tar format (for those who already have a prior version of gzip and want faster data transmission). It works on virtually every Unix system, MS-DOS , OS/2 and VMS .