Hibernate option saves all the currently running applications and turns off the system without any further power consumption. When the system wakes up on the next restart, all the previously running applications are restored. By default, Hibernation is disabled in Ubuntu and it is removed from the Ubuntu’s shutdown menu (for versions 12.04 and onwards). This article will guide you to re-enable the Hibernate feature in Ubuntu systems.

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How To: Enable Hibernation in Ubuntu Systems (Your Own Linux..!)