Now, when you’re finished with the reason you didn’t want your Mac to go to sleep, simply press “Control + C” simultaneously on your keyboard. While caffeinate is running, you won’t notice anything different except for one thing, no matter how long you leave your Mac running, it will not go to sleep. It will look like absolutely nothing happened, but you’ll notice the Terminal window’s status bar says “caffeinate,” which means the command is running. When the Terminal prompt appears, enter the following command and press the Return key: You can also hit the “Command + Space Bar” hotkey combo and enter “Terminal” into Spotlight to run it. You can find it in The “Applications” -> “Utilities” folder. While there are a number of third-party apps that will turn temporarily keep you Mac awake, or you can turn it off in System Preferences, there’s a quicker way to toggle Energy Saver modes on your Mac, and you can do it via a built-in command entered from the command line in Terminal. *I believe the only modifier keys available for this are Shift, Control, Option and Command - you can use any one of them or combinations.While we usually want our Mac’s to go to sleep if they haven’t been used for awhile – saves energy, don’t ya know – there are times we don’t want it to go to sleep, such as when we’re getting ready to give a presentation and such.

Voilà! Now the display will sleep only if you hold down the Command key before moving the cursor to the chosen Hot Corner. Before clicking “Put Display to Sleep” hold down the Command key (or another modifier key*) and then click “Put Display to Sleep”. Open the dropdown for the corner you prefer.

To add a modifier key, open “System Preferences”, go to “Desktop & Screen Saver”, choose the “Screen Saver” tab, and click on “Hot Corners…”. You can add a “modifier key” (e.g., the “Command” key) to the hot corner sequence so that moving the cursor to the chosen hot corner does NOT sleep the screen unless you also push and hold the modifier key. I do not like using a Hot Corner (alone) because too often I would inadvertently sleep the screen by random movement of the the cursor. Sorry for being a Johnny-Come-Lately to this thread, but I just found it.

Mac sleep command