Are there any good video editing programs with a command line interface? I am currently looking for a video editing program which I can control via the command line. The main feature I need is the ability to add some overlay text. Is there anything out there that can do this?

My ideal platform would be Linux, but I would be open to using Windows or OSX if need be.
Avisynth (wiki) is a script-driven app and in conjunction with filters should be able to do the work.