gzip - version 1.2.4

From the README file:

gzip (GNU zip) is a compression utility designed to be a replacement
for 'compress'. Its main advantages over compress are much better
compression and freedom from patented algorithms.  The GNU Project
intends to make this the standard compression program for its system.

gzip currently uses by default the LZ77 algorithm used in zip 1.9 (the
portable pkzip compatible archiver). The gzip format was however
designed to accommodate several compression algorithms.  Future
versions of gzip may optionally support compression with the LZW
algorithm to produce files compatible with compress 3.0 to 4.2.

gunzip can currently decompress files created by gzip, zip (with
restrictions), compress or pack. The detection of the input format is
automatic.  When using the first two formats, gunzip checks a 32 bit
CRC. For pack, gunzip checks the uncompressed length.  The 'compress'
format was not designed to allow consistency checks. However gunzip
is sometimes able to detect a bad .Z file. If you get an error
when uncompressing a .Z file, do not assume that the .Z file is
correct simply because the standard uncompress does not complain.