Simple Bash metronome

Originally posted on Ask Ubuntu as an answer to Where can I find a metronome for music practice?

Usage

metronome.sh [-h] [beats per minute] [beats per measure]

Info

• It plays at 120 bpm in 4 by default
• Maximum 600 bpm in 16, minimum 1 bpm in 1
• The first beat is accentuated.
• You can replace the sound IDs if you want. I just picked ones that sounded good from the Ubuntu 14.04 sound bank. A full list of IDs (names) can be found in the Sound Naming Specification of the freedesktop.org Sound Theme Spec
• On my system, it's accurate to within about 1.5ms per beat, which is not noticeable. (Though I can't remember now how I tested this.)
• metronome-core.sh is just the core stuff - no argument checking, help text, or anything fancy, except checking if sleep succeeds. It will bug out if the BPM is too high, for example.

For example

metronome.sh
metronome.sh 75     # 75 BPM
metronome.sh 120 3  # 120 BPM, 3 beats per measure