I've been using watch a lot lately.
All it does is run a command repeatedly, but it's nice for basic monitoring of sensors or a remote control program (eg, what song is playing).
example: watch -n 2 audtool current-song
will show me the current song being played in audacious right now, updating every 2 seconds


Also, one thing I do pretty regularly is less `which script`, where you'd replace script with the name of some script you wrote and I forgot what it's for/what arguments yo slapped together. ` is the backtick, and even if you should be using $(which script) instead, ` is easier to type lol.