RCS is one of the oldest, if not the oldest, revision control systems (in fact, that's exactly what the name stands for). It may seem incredible, but there's still software around whose history is kept under RCS or a derivative thereof (even without counting CVS in this family).
Despite its age and its distinctive lack of many if not most of the features found in more modern revision control systems, RCS can still be considered a valid piece of software for simple maintenance requirements, such as single-file editing for a single user: even I, despite my strong passion for git, have found myself learning RCS, not earlier than 2010, for such menial tasks.
In fact, the clumsiness of RCS usage when coming from a sophisticate version control software like git was exactly what prompted me to develop zit, the single-file wrapper for git. And so I found myself with the need to convert my (usually brief, single-file) RCS histories to git/zit.
I was not exactly surprised by the lack of a tool ready for the job:
after all, how many people could have needed such a thing? Most
large-scale project had already migrated in time to some other system (even
if just CVS) for which even quite sophisticated tools to convert to git
exist. So I set down to write the RCS/git conversion tool myself: I
studied the RCS file format as well as the
git fast-import protocol,
and sketched in a relatively short time the first draft of
rcs-fast-export, whose development can be followed from its
The first release of the software was quite simple, supporting only linear histories for single files (after all, that was exactly what I needed), but I nevertheless decided to publish my work; who knows, someone else in the internet could have had some need for it.
In fact, what has been surprising so far to me has been the number of
people that have had need for this small piece of software. Since the
public release of the software, I've been contacted by some five or six
different people (among which the most notable is maybe ESR) for
In the current situation it can handle files with branched histories as well as multi-file projects with a linear history. It does not, however, currently support multi-file histories with branching, which is, unsurprisingly, the “most requested” feature at present times. I have actually been looking for a repository with this characteristics, to try and tackle the task, but it seems that finding one such repository is nigh impossible; after all, how many people still have RCS repositories around?