Info-UNZIP ソース
unzip will list, test, or extract files from a ZIP archive,
commonly found on MS-DOS systems. The default behavior
(with no options) is to extract into the current directory
(and subdirectories below it) all files from the specified
ZIP archive. A companion program, zip(1L), creates ZIP
archives; both programs are compatible with archives created
by PKWARE's PKZIP and PKUNZIP for MS-DOS, but in many cases
the program options or default behaviors differ.