SCCS

SCCS , or Source Code Control System is a source code management system designed around the idea of tracking changes to an individual source file.

Implementations

CSSC

The GNU project's implementation of SCCS.

BitSCCS , by Larry McVoy

A Tk GUI is also available.

Tools

sccstool , by Larry McVoy

Was a graphical component of Bitkeeper for displaying changes in a file.