Running emacs lisp programs from command line or script

[Ryan Newton]

Hi all,

If I want to make a command line invokable script to, say, convert emacs 
enriched text documents to plain ones, how do I do it?  I want emacs to 
start up, open said document, save it in plain text mode.  Easy to write 
the emacs lisp code, but how do I call it from the command line.  What's 
the "batch" mode for emacs?

--Ryan