caffeinate on Mac: Keep Your Mac Awake From Terminal

The caffeinate command keeps a Mac awake from Terminal: run caffeinate -d to keep the display on, or plain caffeinate to block idle sleep, and press Ctrl+C to stop it.

Add -t 3600 to stop after an hour, or put a command after it, such as caffeinate -i ./backup.sh, to stay awake only while that command runs. It is built into macOS, needs no admin password and no install.

It does not keep Slack active. The Slack desktop app sets you away 10 minutes after your last keyboard or mouse input on the Mac, whether the Mac is awake or not (Slack desktop 4.52.178 code, checked 7 Oct 2026). caffeinate only stops the instant away you get when the Mac sleeps.

We ran every command on this page on a MacBook with macOS 26.5.2 (Apple silicon) on 30 September 2026, and checked each one with pmset -g assertions. The output is below.

caffeinate flags

The meanings come from man caffeinate. The last column is the assertion each flag created on our Mac, as pmset -g assertions listed it.

Three traps we found on 7 October on the same Mac. -t reads whole seconds only, so caffeinate -t 2h ran for 2.1 seconds with no error. -u without -t takes -m with it after 5 seconds, so caffeinate -dimsu held 3 of its 5 assertions from then on. And -t in front of a command lets go at that time even while the command still runs. The caffeinate command builder checks any line for these and writes one for a time, a clock time or an app.

What pmset showed on our Mac

This is caffeinate -dims -t 20 running, one second in:

$ caffeinate -dims -t 20 &
$ pmset -g assertions | grep caffeinate
   pid 97573(caffeinate): [0x0001aacb000197db] 00:00:01 PreventUserIdleSystemSleep named: "caffeinate command-line tool"
	Details: caffeinate asserting for 20 secs
   pid 97573(caffeinate): [0x0001aacb000597dc] 00:00:01 PreventUserIdleDisplaySleep named: "caffeinate command-line tool"
	Details: caffeinate asserting for 20 secs
   pid 97573(caffeinate): [0x0001aacb000797dd] 00:00:01 PreventSystemSleep named: "caffeinate command-line tool"
	Details: caffeinate asserting for 20 secs
   pid 97573(caffeinate): [0x0001aacb000f97de] 00:00:01 PreventDiskIdle named: "caffeinate command-line tool"
	Details: caffeinate asserting for 20 secs

The timed runs ended on their own. caffeinate -t 2 returned after 2.10 seconds, and caffeinate -i sleep 3 after 3.01 seconds, the length of the command it wrapped. With -w, caffeinate exited as soon as the process it watched ended. After caffeinate -u -t 3 finished, pmset -g assertions | grep -c caffeinate printed 0, so nothing is left behind. None of it asked for a password; it ran as our normal user.

caffeinate -i vs -d

• • caffeinate -i keeps the computer running, but the display can still turn off. Use it for downloads, backups and builds.
• • caffeinate -d keeps the display on. Use it when you want the screen visible, or to stop the screen saver and the lock that follows it.
• • caffeinate -di does both. Flags combine, so caffeinate -dims sets four at once.

For a permanent change instead of a running command, see how to turn off the screen saver on a Mac.

caffeinate examples

# Keep the display on until you press Ctrl+C
caffeinate -d

# Keep the Mac awake for two hours, then stop
caffeinate -di -t 7200

# Stay awake only while a command runs
caffeinate -i rsync -a ~/Projects /Volumes/Backup/

# Stay awake until another app quits (find its PID with pgrep)
caffeinate -i -w "$(pgrep -x Transmission)"

# Run it in the background and keep using the same Terminal window
caffeinate -d &

Check that it is working with pmset -g assertions | grep caffeinate, as in the output above. Without the grep, the same command lists everything else that keeps a Mac awake; on our Mac that included the Amphetamine app and an Electron app. More in why is my Mac not going to sleep.

How to stop caffeinate

caffeinate and the MacBook lid

Closing the lid puts a MacBook to sleep even with caffeinate running, unless the Mac is on power with an external display, keyboard and mouse attached. caffeinate keeps an open Mac awake; it does not replace clamshell mode. With no display attached, the admin command pmset disablesleep keeps a closed Mac awake, until you set it back to 0. Lid-closed options for Mac and Windows are in keep a laptop awake with the lid closed.

Does caffeinate keep Slack active?

No. We tested the same thing with the Caffeine app: Slack stayed green until minute 10, then went away with the screen still on. The full test is in does Caffeine keep Slack active.

caffeinate removes one trigger, the Mac sleeping or locking, which sets you away at once. Slack's idle timer reads the Mac's idle time, and caffeinate creates no input. caffeinate -u wakes the display for a few seconds but does not reset the idle counter. The Mac-specific rules are in keep Slack active on Mac, and every method is compared in how to keep Slack active.

If you would rather click a menu bar icon than type a command, we compared Amphetamine, KeepingYouAwake, Caffeine, Lungo and KeepAwake in the best app to keep a Mac awake.

caffeinate on a work Mac

caffeinate is built in and needs no admin rights, so it works on most managed Macs. A screen lock enforced by your company through MDM still applies. Lock Screen settings that stop locks for good are in keep a Mac screen from locking. For Windows and Linux equivalents, see keep a work computer awake without admin rights.

FAQ

Does caffeinate need sudo?

No. It runs as your user. Every command on this page ran without a password.

Does caffeinate survive closing Terminal?

Closing a Terminal window sends a hangup signal to what runs in it. In our test that signal stopped a plain caffeinate at once, while one started with nohup caffeinate -t 60 & kept running. Use nohup if you want to close the window.