PKUNZIP

from The Free On-line Dictionary of Computing (8 July 2008)

PKUNZIP

   <tool, compression> A program to unpack {archives} created by
   {PKZIP}, written by {PKWARE, Inc.} and released as
   {shareware}.  Versions exist for {MS-DOS}, {Microsoft Windows}
   and {Open VMS}.  PKUNZIP is no longer distributed, its
   functions having been incorporated into PKZIP.

   (1999-01-07)