No option to hibernate/shutdown in GNOME 3?

Solution 1:

Hold down the Alt key and Suspend will change to Power off.

Solution 2:

Install following extension will add "Shutdown" and "Hibernate" to your menu:

yum install gnome-shell-extensions-alternative-status-menu

From: http://mygeekopinions.blogspot.com/2011/06/how-to-add-shutdownhibernate-menus-in.html

Solution for Ubuntu:

sudo add-apt-repository ppa:ferramroberto/gnome3
sudo apt-get update
sudo apt-get install gnome-shell-extensions-alternative-status-menu

From http://www.noobslab.com/2011/10/status-menu-gnome-shell-extension-for.html

Solution for Debian (should also work in Ubuntu):

Install gnome-tweak-tool:

sudo aptitude install gnome-tweak-tool

Restart the gnome-shell (Alt-F2 and type "r", then return.) Then open gnome-tweak-tool and go to "Shell Extensions" and set the option "Alternative Status Menu Extension"

Solution 3:

I've googled for the answer too, but before I read any provided, I had an insight: just press the power button on your device, a menu will pop up.