What's the full name of command "df"?
 

du - estimate file space usage
df - report file system disk space usage

I think du is short for "disk usage".
But what about df?

disk free - it reports the free (available) space on your filesystem(s)

df = Disk Free - http://en.wikipedia.org/wiki/Df_(Unix)
du = Disk Usage - http://en.wikipedia.org/wiki/Du_(Unix)

posted at the same time...
rfernandez, you sir, owe me a beer. LOL!

thank you.

Well, I can't never say "no" for a beer. 8-D