uptime command

uptime

The uptime command prints the current time, the length of time the system has been up, the number of users online, and the load average. The load average is the number of runnable processes over the preceding 1-, 5-, 15-minute intervals. The output of the uptime command is, essentially, the heading line provided by the w command.

Example
8:11pm up 6 day(s), 16:09, 1 user, load average: 0.23, 0.25, 0.24