Ubuntu contains a very few shortcut key configuration utility which does not permit you to give hotkeys to your own applications or scripts. Because of this limitation, we can use the built-in gconf-editor utility to allocate them ourselves.
First you would like to load gconf-editor by Alt+F2 Run dialog.

Once in the application, browse to the following key.
apps \ metacity \ keybinding_commands
You will observe the lots of value in right side. These are existing command that you can make for allocate to shortcut key in the next step.
Double-click on command 1 and type a entire path to your script or run that you are trying to run.

Now browse the key “global_keybindings”, which is directly above the one we were on.

Here you will want to select run_command 1. Enter in the shortcut key in plain text. For instance, for Alt+T, you will do <Alt>T. You could use <Ctrl>T or <Alt><Ctrl>T, or at all you want to allocate to the key.

You can also create your own command using keybinding_commands. Ans allocate them in the gobal_keybinding if you have. just keep it mind that keybindings will start using run_(name of command)