Programmatically managing VCS

I have the following issue: a script periodically (once a day, for instance) pulls rarely-changing mostly-textual data from various sources.  I wish to keep a history of the state before each script run.  It certainly sounds like a job for VCS control system.

I remember someone here praising Mercurial as the best VCS ever.  Does it have a fairly stable and reliable command-line interface such that (given enough information) it will not interactively prompt the user (which is a non-interactive script)?

just use git you git!