caffeinate on Mac: Keep Your Mac Awake From Terminal

caffeinate is a command built into macOS that keeps your Mac awake. Open Terminal and run caffeinate -d to stop the display from sleeping, or caffeinate with no flags to stop the system from idle sleep. It runs until you press Ctrl+C. 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 needs no admin password and no install.

It does not keep Slack active. Slack sets you away 10 minutes after your last input in the Slack window, whether the Mac is awake or not. caffeinate only stops the instant away you get when the Mac sleeps. To keep your dot green without the Mac, Slack Green keeps your presence active from its own servers during the working hours you set.

caffeinate flags

From man caffeinate:

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.

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. The output lists PreventUserIdleDisplaySleep or PreventUserIdleSystemSleep held by caffeinate.

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. 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 counts only input inside the Slack window, and caffeinate creates none. caffeinate -u wakes the display for a few seconds, which is still not input in Slack. The Mac-specific rules are in keep Slack active on Mac, and every method is compared in how to keep Slack active.

If the goal is a green dot, not an awake Mac, Slack Green keeps it active on your schedule from a server, with the lid closed. For the same question about the Amphetamine app, see does Amphetamine keep Slack active.

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

What does caffeinate do on a Mac?

It creates power assertions that stop the display, the system or the disk from sleeping, until you stop it or its time limit ends.

How do I keep my Mac awake from Terminal?

Run caffeinate -d for the display, or caffeinate -di -t 3600 for display and system for one hour.

How do I stop caffeinate?

Press Ctrl+C in its Terminal window, or run killall caffeinate.

Does caffeinate need sudo?

No. It runs as your user.

Does caffeinate keep Teams active?

No. Teams sets you away after 5 minutes of inactivity in Teams, whether the Mac is awake or not.