Keyboard shortcuts are preset in the system, but you can add new ones
or change them easily. For instance, change the default shortcut
Ctrl+Alt+T (Run a Terminal) to Win+R (press R while holding down the
Windows key, also known as Super key) by the following steps:
-
Go To System > Preferences > Keyboard Shortcuts
-
Browse to Desktop > "Run a terminal"
-
Click on the Shortcut, and it shows "New shortcut..."
-
Press Win+R, and it shows Mod4+R
-
Click the Close button and try the new shortcut.

To disable a shortcut, press Backspace when it shows "New shortcut..." after the step 3 above.

Shortcuts begin with XF86 refer to special keys available to some multimedia keyboards.

Keyboard shortcuts can also be set by changing keybinding values with Configuration Editor. Press Alt+F2 and enter
gconf-editor,
then navigate to apps > gnome_settings_daemon > keybindings, or
apps > metacity > global_keybindings and window_keybindings.
Related Posts : Ubuntu,
Ubuntu Panel