How to Power the computer on with command??!!

Hello world:)
I was wondering can we wake up the PC by command or bat? I want to let PC power off in a period of time(like 30 seconds) and then boot again by itself. Then off and on. For testing purpose. Can we do it by any command?

I wrote a bat to let user enter the times that whom wants to execute. But don't know how to wake PC up!

Thx for any help