If you start long commands you might want to get warned by a sound when one finishes.
On Mac OSX you can do like this
command; afplay /System/Library/Sounds/Ping.aiff
to get notified of when a command finishes.
If you also want to have a feedback based on whether the command succeeded or not:
command && afplay /System/Library/Sounds/Glass.aiff || afplay /System/Library/Sounds/Basso.aiff
afplay xxx for
say "something" to have the computer actually tell you when it's done!