Show how long system has been running.
The uptime utility displays the current time, the length of time the system has been up, the number of users, and the load average of the system over the last 1, 5, and 15 minutes.
14:12 up 4 days, 7:06, 2 users, load averages: 0.23 0.19 0.20
“Life is all about timing... the unreachable becomes reachable, the unavailable become available, the unattainable... attainable. Have the patience, wait it out It's all about timing” - Stacey Charter
uptime man page - Apple.com
shutdown - Shutdown or restart OS X