Every Monday, we'll show you how to do something new and simple with Apple's built-in command line application. You don't need any fancy software, or a knowledge of coding to do any of these. All you need is a keyboard to type 'em out!
Powering off your Mac properly can avoid incurring problems like system file corruption. All it takes is a little patience and the right routine. You can use the Apple menu to turn off your computer, put it to sleep, or restart it, but with Terminal you can select even more options for shutting down your Mac, including logging off all users and setting up certain times for your Mac to shut down. These commands are extremely handy if you manage a server or remote Mac through SSH. Read on to learn more.
To turn off your Mac, you can use the following command to do so immediately:
sudo shutdown -h now
The “-h” (or “halt") tells the computer to shutdown down. Once issued, the computer will immediately go down after you type in your administrator password. Your user account must have administrator privileges in order to invoke the shutdown commands.
To reboot your Mac, the following command can be used to instantly restart:
sudo shutdown -r now
The “-r” option executes the “Reboot” function in the shutdown command. Once issued, the computer will immediately go down, and will then reboot automatically.
To put your Mac to sleep, or put it in a power saving mode, the following command can be used:
sudo shutdown -s now
Once issued, the computer will enter its power saving mode. If you are using SSH, ensure that the “Wake for network access” option is enabled in System Preferences > Energy Saver, or else the remote computer will be unresponsive for remote access until woken locally by pressing the power button, moving the mouse, or tapping a button on the keyboard.
In the above commands, we used the “now” specifier, which told the computer to begin the shutdown procedure immediately. However, you can also tell the computer to perform any of the above functions at a certain time using the two methods below.
You can have the system shutdown, restart, or sleep at a certain time by replacing “now” in the above commands with a date and time format like this: yymmddhhmm. Where yy is the year, mm is the month, dd is the day, hh is the hour, and mm is the minutes. The time is specified in a 24-hour time format.
So, if for instance, we wanted the computer to restart at 3:30pm on January 1, 2013, we’d issue the following command:
sudo shutdown -r 1301011530
After executing the command, you’ll be given the date and time of the shutdown in your system’s format, along with the process id (pid).
You can also execute a shutdown procedure after a certain number of minutes has elapsed from the current time. To do this, you’ll replace “now” in the above statements with the following format:
+number
Where “number” is the number of minutes after the current time that the computer will execute the command. So, if you wanted to shutdown your Mac in 30 minutes, you’d issue the following command:
sudo shutdown -h +30
Cory Bohon is a freelance technology writer, indie Mac and iOS developer, and amateur photographer. Follow this article's author, Cory Bohon on Twitter.
yojo056
July 03, 2012 at 1:22pm
Cory, I'd just like to say that your Terminal 101 articles are one of the main reasons I visit maclife.com. Keep up the good work at making us even more nerdy.
mprusse
July 02, 2012 at 9:01pm
What's the command to log off all users before shutdown as mentioned in the opening paragraph? Thanks.
corybohon
July 03, 2012 at 11:34am
When you have users logged into the system and initiate any of the shutdown commands, you'll get a message printed to the screen.
corybohon
July 03, 2012 at 11:37am
The Terminal is really for power users, allowing them to do things without messing around with the UI. Simply type the command, and you're done.
The second important advantage of using the Terminal to complete commands is that if you use SSH to connect to a Mac remotely, you can easily issue commands to the remote Mac. Using the tips above, you can shutdown, reboot, or sleep the Mac remotely just by typing in a command. (By remote, I mean, you could do this with a machine around the world). That's the true power of the Terminal.
DavidABQ
July 02, 2012 at 6:48pm
Hi,
Great article, I look forward to future Terminal 101 articles.
I have a question relating to this article:
For the Timed Shutdown examples, is there a way to stop the delayed shutdown process once the command has been issued (in case the need to reboot resolved itself before the actual command has done it job)?
Thanks, David
corybohon
July 02, 2012 at 6:57pm
You can cancel a shutdown by issuing a pkill (process kill) or a killall command on the shutdown command. So, to cancel a shutdown, simply enter one of the following commands into a Terminal window:
pkill shutdown
sudo killall shutdownUsing the second (killall) command, you'll be prompted to enter your password. You'll get an error message that "No matching processes were found" if the shutdown command is no longer running for a timed shutdown.
