If you Google "common linux commands" and check the top few lists you'll find that "df" is on all of them, so it really is considered common by people other tha

If you Google "common linux commands" and check the top few lists you'll find that "df" is on all of them, so it really is considered common by people other than me. In the age of the GUI, though, I can see how people might never need to learn it.