The developers implemented the HUD in Ubuntu 12.04, HUD adopted and further implemented into upcoming releases, such as Ubuntu 12.10 and Ubuntu 13.04.
Essentially, the HUD presents itself as an intelligent menu (a smart menu guesser), meaning, while having opened an application, typing certain characters (like for example
cu) after hitting the keyboard's
Alt key, summons in the HUD natural, commonly-used actions (such as
cut); pressing the
Enter key, executes the command.