There are a lot of applications that you can use/install to prevent your mac from sleeping such as Caffeine, Jiggler, or InsomniaX. But what if you’re too lazy to install those applications in your Mac, but still wanted to prevent your Mac from sleeping?
Well, the answer is by using a simple Terminal Command . To do this, open the Terminal (Applications > Utilities > Terminal) and enter the following command:
That’s it your Mac will not sleep so long as you do not close the Terminal. To enable your Mac to sleep again, simply hit Control + C or close the Terminal.