I like Perforce it is fairly easy to use. If you want to go old school there is RCS or SCCS. GNU provides source code (for SCCS there called CSSC). Though *C

I like Perforce it is fairly easy to use. If you want to go old school there is RCS or SCCS. GNU provides source code (for SCCS there called CSSC). Though *CS are per file not per logical commit. IIRC Perforce actually used RCS under the covers for storing the deltas.