Add keyboard shortcut for shutdown dialog

If you want to add a custom keyboard shortcut to open the shutdown menu, you have to:

• go on Menu --> Keyboard, and then on the "Shortcuts" tab
• click on the "+" button
• give a name you desire and the following command:  gnome-session-quit --power-off
• Select the new shortcut and press the key combination you want to assign to it
• Close, and you're done!

You may find also this post useful: How to add hibernate option to Mint 13

How to add hibernate option to Mint 13

If you have installed Mint 13, one of the first things you'll notice is that there is no hibernate option in the shutdown window.
Although there is no way to add the option from GUI, you can simply do it by following these instructions:

• open a Terminal (CTRL+ALT+T) and type sudo gedit /etc/polkit-1/localauthority/50-local.d/com.ubuntu.enable-hibernate.pkla (or another text editor instead of gedit); then insert your password in the terminal
• add the following lines at the end of the file, then save:
  

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

Now (or in some cases after restart) you will see the hibernate option when you click the poweroff button..