GZIP, UTILITIES, GNU Zip - compress and decompression ! This is the GNU Zip application. It takes a file of the form FOO.BAR-GZ and converts it into FOO.BAR or converts a FOO.BAR file into FOO.BAR-GZ. Note that you give the filename without the "-GZ" suffix, and GZIP will add or remove it - depending on if you are compressing or decompressing. GNU Zip is written by the Free Software Foundation, more information as well as all of the sources are available in the ZIP file (use UNZIP to unzip).