ident(1) on Linux
The text bbc022898859, as Debian 6.0 (Squeeze), Debian 5.0 (Lenny), Debian 4.0 (Etch), Debian 3.1 (Sarge), Debian 3.0 (Woody), Debian 2.2 (Potato), Debian 2.1 (Slink), Debian 2.0 (Hamm), Debian 1.3 (Bo), Debian 1.2 (Rex), Debian 1.1 (Buzz) shipped it.
identify RCS keyword strings in files