Show total size of folders and contents

This one helped me find several 2GB log files that brought disk usage down from 92%

du -ah --max-depth=1

Start from root and work your way through folders until you find the offending files. You can change the depth to speed things up. You can also run this command from anywhere to check total usage:

df -ah

Of course you won't need to do any of this because you will be rotating your non-verbose log files anyway