I've been using arecordmidi and it's giving me fits. Main problem is: it drifts!!
If I fire up Hydrogen or klick or any kind of JACK transport accurate click track, and
then play to it, and record the result using arecordmidi, and then play it back using
aplaymidi, what I get starts out in sync with the metronome or drum machine, but then
drifts, noticeably.
What I'm not sure of, is which is drifting: arecordmidi or aplaymidi. Not sure how to
determine this. But if there were a command-line MIDI recorder and player that was
accurate to the JACK clock, I'd rather use that.
-ken