The cvs product contains everything you need to perform industrial scale 
revesion control of whole directory structures of files.

Version v1_9 of the cvs product includes:

diffutils	version 2.7
		The GNU diffutils distribution, including diff and diff3 with
		extended options for various file comparison report formats
		and finding differences in binary files.

rcs		(new version!) version 5.7
		The RCS Revision Control System, which provides tools
		to keep a complete revision history of a file in a
		corresponding RCS file.  Programs include:
		    ci	    "check in" -- add a revision to an RCS file
		    co	    "check out" -- get a particular revision of a file
			    from an RCS file
		    rcs	    Administrative utility command
		    rlog    Print log messages associated with revisions
		    rdiff   print differences between revisions

cvs		(new version!) version 1.9
		The Concurrent Versioning System, provides utilities to
		manage a central repository of RCS files, and check out,
		change, find differences, and generally maintain whole 
		directory trees of files, with multiple users working on
		distinct checked-out copies.

reserve		version 1.0
		Script to maintain a reservation file and lock/unlock
		sources in a CVS repository.