For diagnostic purposes (or if you’re just curious) it can be useful to check your Mac system uptime. This lets us see how long its been since your Mac was rebooted. Macs are generally very stable and you don’t have to reboot very often. This means that your uptime can reach impressive lengths, like mine at 27 days.
Mac System Uptime
The Terminal command we’ll be using is a simple, one-word command:
That’s it. This will show you how the time, how many hours or days of uptime, number of users, and CPU load averages. If you want to check your Mac’s reboot history, you can enter this command:
This gives you a nice list of the dates that your Mac has been restarted.