I came across this tool recently, which I have been very impressed with. Though not really for every-day use, ncdu can be very helpful when tuning up your boxen, as you can quickly scan through multiple hard drives to find where all your disk space is going.
To use it, simply enter / in the prompt (start it up with no arguments), and make sure the “One filesystem” option is not checked (pressing X checks or unchecks it). Note that the backspace key actually did a forward-backspace for me (it deletes items in front of the cursor, rather than behind, as I’m accustomed). This may just be that my terminal isn’t set up properly (Mac Terminal connecting to a Ubuntu box as xterm-color), so YMMV. Let it run for it a bit (a progress window appears showing it going through all of your disks and folders). On my Ubuntu machine with a pair of SATA drives (software RAID 1), it took less than 30 seconds to go through everything.
Once the scan is complete, you’ll see a list of directories and files located at the path you put in originally. You can use your arrow keys to navigate into and out of directories, and you’ll get info about the sizes to the left. What’s especially useful, though, is the sorting: use the “s” key to sort by size (twice to switch between ascending and descending order). Simply sort by disk usages, then enter directories to find what’s using up the most space – you may be surprised.
Using ncdu, it took me all of 10 seconds to zero in on my biggest disk drainers (home directories and logs). If you’re looking for a useful tool to explore your filesystem and nail down your biggest disk hogs, give ncdu a spin.
Resources
The ncdu homepage
Zen Sysadmin: Finding the Disk Hog
RHEL: Implementing Disk Quotas
All about Linux: Disk Quotas in GNU/Linux explained
View your filesystem via the web using WebDisk
