This is a tool called RRCS, Revised Revision Control System.

GOALS:  This is intended to be a tool which -
 - is completely compatible with existing ,v files,
 - while being more automation-friendly than RCS,
 - and with a user interface resembling that of git, with which many
   people are already familiar.

For now, I'm prototyping the git-like user interface with a
shellscript, `./grcs'.