check system uptime in linux

The below command displays a one line summary showing...

Example: uptime
11:42pm up 18 days, 8:45, 1 user, load average: 0.00, 0.00, 0.00

* Current time (11.42pm)
* Number of days since last boot (up 18 days)
* Number of users logged in (1 user)
* System utilization for the last 1, 5 and 15 minute intervals (load average