Disable Sleep on a Mac from the Command Line with caffeinate

Aug 3, 2012 - 14 Comments

Caffeinate causes a Mac to avoid sleeping via command line

You’ve always been able to temporarily prevent a Mac from sleeping by using the pmset noidle command or a hot corner, but with OS X Mountain Lion, Apple has bundled a command line tool dedicated to sleep prevention much like the popular Caffeine app, and appropriately, named it caffeinate.

At it’s most simple usage, caffeinate just prevents sleep entirely, but you can modify the command with various flags to prevent just the display from sleeping, provide a specified time to avoid sleeping, prevent sleeping while a command runs, and more. A few useful examples are discussed below.

To temporarily disable sleep, run this command from Terminal:

caffeinate

You can also run caffeinate for a pre-determined amount of time to prevent sleeping, say for 4 hours while you download something, and then run it in the background by adding & to it:

caffeinate -t 144000 &

The number attached to the -t flag is the amount of time in seconds for sleep to be disabled on the Mac.

Caffeinate can also be attached to other commands to prevent the Mac from sleeping while the command runs:

caffeinate [command_to_run] -arguments

That causes the Mac to avoid sleep only as long as it takes to run the command provided, after which the normal sleep rules apply.

Heads up to MacWorld for the tip

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Posted by: William Pearson in Command Line, Mac OS X, Tips & Tricks

14 Comments

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  1. Aberto I says:

    “To temporarily disable sleep, run this command from Terminal: caffeinate”

    Temporarily… How much time?
    And how to turn to a normal situation?

    • Will says:

      Sleep is prevented for as long as caffeinate runs, if you stop caffeinate or kill the process it will return to normal behavior. Likewise, if you set a time limit it will only prevent sleep for the specified time before returning to normal behavior.

    • Daizy says:

      “To temporarily disable sleep, run this command from Terminal: caffeinate” Temporarily… How much time? And how to turn to a normal situation?

  2. Vlad Dj Kax says:

    Or.. you can download Caffeine from the Mac App Store..

    http://itunes.apple.com/us/app/caffeine/id411246225?mt=12

  3. Vlad Dj Kax says:

    One thing that doesn’t seem to work with Caffeine (unless I’ve made a mistake..) is that, once you lock your session, it seems to stop preventing the Mac from sleeping …

    • Aberto I says:

      It is what I was asking above: “And how to turn to a normal situation?’”

      What is the terminal instruction?
      decaffeinate?? :D

      • MacBookPro:~ yapchinhoong$ caffeinate &
        [1] 324
        MacBookPro:~ yapchinhoong$ ps -ef | grep caffeinate
        501 324 306 0 11:05PM ttys001 0:00.00 caffeinate
        501 326 306 0 11:05PM ttys001 0:00.00 grep caffeinate
        MacBookPro:~ yapchinhoong$
        MacBookPro:~ yapchinhoong$ kill 324
        501 330 306 0 11:05PM ttys001 0:00.00 grep caffeinate
        MacBookPro:~ yapchinhoong$

        • MacBookPro:~ yapchinhoong$ caffeinate &
          [1] 324
          MacBookPro:~ yapchinhoong$ ps -ef | grep caffeinate
          501 324 306 0 11:05PM ttys001 0:00.00 caffeinate
          501 326 306 0 11:05PM ttys001 0:00.00 grep caffeinate
          MacBookPro:~ yapchinhoong$
          MacBookPro:~ yapchinhoong$ kill 324
          MacBookPro:~ yapchinhoong$ ps -ef | grep caffeinate
          501 330 306 0 11:05PM ttys001 0:00.00 grep caffeinate
          MacBookPro:~ yapchinhoong$

    • Kiwiiano says:

      I suspect you are mistaken, VDK. If I toggle Caffeine on, it stays on indefinitely, although this MBP blacks out if I move the cursor into the top right corner or if I close the lid. By control clicking the menubar icon I also have the options to stay awake for 5, 10, 15, 30, 60 or 120 minutes. Beats messing around with Command lines.

  4. Jay says:

    there is a much simpler command with nothing being required to be installed.

    “pmset noidle” <<< as long as this terminal session is running, your computer will not sleep.

  5. Mteacher says:

    The current build of Caffeine doesn’t work properly under Mountain Lion – ML’s set sleep parameters override Caffeine’s capabilities in some instances.

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