For several times I wondered what was the exact time my machine booted, woke up or slept. So, I did a little investigation to find out that's actually very simple to get those answers.
Using the Mac OS X Terminal, you can run the following commands:
- For System Boot Time, use: systcl -a | grep kern.boottime
- For System Sleep Time, use: sysctl -a | grep sleeptime
You should get results similar to the picture below
- For System Wake Time, use: sysctl -a | grep waketime
You should get results similar to the picture below
I typically use the "uptime" command (just type uptime on the Mac OS X Terminal) to find out how long my machine has been powered on.
Lastly, you can get a short history of the machine boot using the "last reboot" command (just type last reboot on the Mac OS X Terminal) to get the last three boots of the system.
You can get the same information reviewing system log files but I think opening the terminal and typing a few commands easy enough to get the information you're looking for.
