The df command in Linux explained
The df command shows how much space is used on each mounted drive. It is one of the most useful commands for anyone using a live USB drive or a fresh Linux install.
Syntax
df [-h]
Examples
df -h: sizes in readable units
Tip
Look at the Use% column to spot a drive that is filling up.
Keep learning
New to the terminal? Start with Linux terminal basics. You can try every command safely from a live session: see how to try Linux without installing it. Run man df in a terminal for the full manual.
Frequently asked questions
How do I see every option for df?
Run man df for the full manual, or try df --help for a short summary.
Do I need sudo to run df?
Not for your own files. You only need sudo when the command changes something owned by the system or another user.
Is it safe to practise df on a live USB drive?
Mostly yes, because a live session starts fresh each time. Be careful with commands that write to your internal disk, such as rm on a mounted drive or dd.