uptime

Show how long the system has been running and load averages.

low risk

interactive breakdown — edit the command and press Explain
$ 
What it does

uptime displays current time, system uptime, number of logged-in users, and load averages for 1, 5, and 15 minutes. Load average represents the number of processes in runnable or uninterruptible state — should generally stay below CPU core count.

Examples
uptimeShow uptime and load averages · explain & risk-check →
uptime -pShow uptime in pretty format (e.g., 'up 2 days, 3 hours') · explain & risk-check →
uptime -sShow exact boot timestamp · explain & risk-check →
cat /proc/uptimeMachine-readable uptime in seconds · explain & risk-check →
Pro tip

Compare load average to your CPU count: `nproc` tells you cores. Load of 4.0 is fine on a 8-core box but critical on a 2-core one.

Related
top vmstat uname
Open the full explainer →More in System & Processes

Reference text is hand-written and may be incomplete — check man uptime for your version. Test destructive commands on a non-production system first.