In Ubuntu 12.04 and newer versions,Hibernation option is disabled by default.So you need to manually enable hibernation option via Terminal.This article will show you how to do it.

What is Hibernation ?

When the system is hibernated, the computer saves the contents of its random access memory (RAM) to a hard disk. When it is resumed, the computer is exactly as it was upon entering hibernation.For example if you hibernate with your Word Text processor open with some contents then upon resuming it will be at the same state.

Hibernation is also known as suspended to disk mode.

Enable Hibernation in Ubuntu 12.04, 12.10 and 13.04

First you need to check whether the hibernation correctly works or not.So,execute the following command in terminal

sudo pm-hibernate

If system is able to restarted with same state then no problem with the process.Now to enable it you need edit the system file.To do so enter the following commands in terminal

sudoedit /etc/polkit-1/localauthority/50-local.d/com.ubuntu.enable-hibernate.pkla

Now add the following codes in it

[Re-enable hibernate by default]
Identity=unix-user:*
Action=org.freedesktop.upower.hibernate
ResultActive=yes

Save the file using command Ctrl-O and exit the editor by pressing Ctrl-X

Now restart the system,Hibernation option will be back to your Power menu.If you didn’t get it then execute the following command (the last one 🙂 )

sudo update-grub

Now you are ready to go.