A keyboard shortcut is a quick way to perform an operation without using a menu (a command key) or to type a character not present in the standard keyboard layout. By pressing and holding a modifier key, or a combination of modifier keys, then typing a character, the action is performed without having to move one's hands from the keyboard.
Some software is available to improve the ability to control the Macintosh by keyboard shortcuts. For example the control panel MacroKey or the system extension KeyQuencer. The latter is accompagnied by a Scipting Addition to support AppleScript and a separate Macro Editor. Both allow to invoke any sequence of keystrokes just by hitting a keyboard shortcut. KeyQuencer also provides a lot of extra functionality, as mouse actions, application launching/switching etc. within an own, simple language.