Awesome, I didn't know about awk and sed, so that's why I mentioned grepping the output from df. I did some quick googling before asking, but from what I saw, I wasn't likely to find much useful info without spending a long time digging through the garbage to get it.
Bash scripting is definitely a useful thing to know, and it gives me an excuse to "program" some stuff once in a while to satify my occasional code craving, lol. I figured I'd run something like that while running some large emerges, like gnome, just in case I'm getting close to full. I don't have a huge partition to play with in linux at the moment. I'm already nearing the 50% mark :/
EDIT: Correction, nearing the 70% mark :S by the time gnome is installed it's gonn be full :< (well, that, and when wesnoth is finished)