The free command in Linux explained
The free command shows memory (RAM) use. It is one of the most useful commands for anyone using a live USB drive or a fresh Linux install.
Syntax
free -h
Examples
free -h: totals in readable units
Tip
The available column is the best guide to what programs can still use.
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 free in a terminal for the full manual.
Frequently asked questions
How do I see every option for free?
Run man free for the full manual, or try free --help for a short summary.
Do I need sudo to run free?
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 free 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.