gzip, gunzip, zcat—compresses or expands files

gzip [ -acdfhlLnNrtvV19 ] [-S suffix] [ name ... ]

gunzip [ -acfhlLnNrtvV ] [-S suffix] [ name ... ]

zcat [ -fhLV ] [ name ... ]

gzip reduces the size of the named files using Lempel-Ziv encoding (LZ77). Whenever possible, each file is replaced by one with the extension .GZ, while keeping the same ownership modes, access, and modification times.