`uptime` - tell how long the system has been running

uptime [-p]

Options you will use

-p, --pretty: Show uptime in a human-readable form.

Gotchas

The three load numbers are the 1, 5 and 15 minute averages of runnable (R) PLUS uninterruptible (D) processes. High load with an idle CPU means D-state - usually blocked I/O.

Taught in

Try uptime in a real terminal Free, in your browser - a real Ubuntu terminal to try it in, with missions that check your work.