In Ubuntu 12.04, due to an apparently large number of unsupported systems, the Hibernate option was removed, both from the System menu and the system’s Shut Down dialog window.
What this means is that although the feature is still present in Ubuntu (if you know the Terminal command, you can still hibernate your system), it’s not easily accessible via the standard menus or the shut down dialog, as shown below.
Instead, users need to either completely shut down their systems, or use the Suspend option instead. For some people, this is fine, but for others, it won’t be sufficient. This is because of the differences between Hibernating and Suspending.
Hibernate saves the state of a user’s system, saves it and completely turns off the computer, so it uses no power while hibernating. Turn the system back on, and the computer should be in exactly the same state as before hibernating (the same programs will be open). Suspending the system, on the other hand, does the same thing, except the computer never really shuts down. The state of the system is saved to RAM, then the computer “goes to sleep” for lack of a better term; in this state, however, it continues to use a small bit of power, so a laptop in Suspend mode, for instance, would eventually drain the battery.
As mentioned, while the Hibernate option isn’t shown in the System menu, it is possible to get it back. First, however, you’ll want to see if your system supports the Hibernate feature. To check it, first open up the Terminal.
Now type sudo pm-hibernate to attempt to hibernate your system.
If everything goes according to plan, the state of your open documents and programs will be saved, and the computer effectively shut down. When you start it back up again, your computer will boot up, returning you to the same point, including documents and websites, the same as before you hibernated. If this works as expected, it’s safe enough to continue with the rest of the procedure. Obviously you don’t want to test your system’s hibernate support with critical information unsaved in your documents, on the chance it doesn’t work as hoped.
Now that you’ve tested the hibernate feature, here’s how to add the option back to the System Menu.
In the Terminal, type sudo nano /etc/polkit-1/localauthority/50-local.d/com.ubuntu.desktop.pkla to open (as root) a file called com.ubuntu.desktop.pkla, using “nano,” a Terminal-based text editor.
Now type (or copy and paste) the following four lines into the empty document:
[Re-enable hibernate by default]
This tells your system to activate the hibernate feature for all users. You could specify a particular user in the second line, but this way the option will be available for everyone. Once you’ve pasted or typed this in, hit the Ctrl-x keyboard combination to quit nano, then hit the “y” key to save changes, and finally “Enter” to save the changes using the original file name.
Now go ahead and either log out and back in, or restart your system completely.
You’ll notice that the above window already has the Hibernate option in it; this change is immediate, but logging out or restarting is necessary for the option to show up in the System Menu, as shown below.
As mentioned, this fix won’t work for everyone. Rather, the fix will work, but since the feature itself doesn’t work for every system, the fix will be worthless for some people. However, if you’re one of those people who have a system that supports the Hibernate option, this is a good trick to know.