Many of the GNU versions of common *nix applications such as du, df, etc, support a special flag '-h', which means "Human readable format." This is quite useful on larger devices to try and decipher all those numbers. For example, 'df -h' gives me this:
Filesystem Size Used Avail Use% Mounted on /dev/hda2 17G 9.3G 6.4G 60% /
On my laptop, and 'du -h' gives me:
... 8.0k ./opt/gnome/cron.daily 16k ./opt/gnome/medusa 12k ./opt/gnome/profile.d 12k ./opt/gnome/oaf 8.0k ./opt/gnome/pam.d 8.0k ./opt/gnome/security/console.apps 12k ./opt/gnome/security 968k ./opt/gnome 972k ./opt ...
Which is a whole lot friendlier than counting digits to figure out how much space is really used or available.