Are there any apps out there that can tell me what files or directories are taking up the most space on my partitions? For example, lets say I have a server w/ a partition that normally sits around 75% used and one afternoon I get an alert from Nagios saying my disk is at 99%, or even worse 100%. Usually it is a log file that gets our of hand and fills of the disk. Are there any apps out there that can tell what file or directories are taking up several gigs ouf nowhere? I am aware of 'du', but I don't see any sort option. I suppose I could 'cd /; ls -R --sort=size > results.txt', but that does not seem to be a very efficient method. Any suggestions?

Doing a ls on all files and directories would take forever and cause issues I would think.. first narrow down what directory is taking up the most space.. with either df or du on /

Then start doing your digging.. like say for instance /var is getting quite large in usage which is normal cause logs get stored there.. you could do a: du -h /var/log | sort -n

And that would sort the files and directories in order, smallest to largest, etc.

Ahh...pipe to sort...that has potential ;-), thanks.