[TxMt] question: save hook

[Piero D''Ancona]

I'd like to do a series of things automatically
each time I save a modified file. E.g. change
the name of the file adding a timestamp to it,
etc. What is the simplest way? Probably to
create a command which does all the stuff, and
assign the shortcut CMD-S to it. I do not
like this idea, emacs' hook mechanism sounds
the right way to achieve this, but I could live with it.

Anyway: how can I say TextMate to save the
open (modified) file? I mean, from inside my
command?

Thanks,
Piero