I was shown this maybe my second day on my first job with the title “System Admin”.
It worked on Solaris 2.4, and has continued to be useful through AIX, HPUNIX, Red Hat, Ubuntu, Debian, Gentoo, Crunchbang, other variants of Solaris, BSD, etc. One of the best parts of being a UNIX sysadmin instead of say Windows, is that what you learn gets added to over time…
du -ak | sort -nr | more
It uses resources, so not a great idea on a loaded system without taking care you don’t cause it to fall over.
–doug