Keyboard shortcuts are typically an alternate means for invoking one or more commands that would otherwise be accessible only through a menu, a pointing device, different levels of a user interface, or via a command console. Keyboard shortcuts generally expedite common operations by reducing input sequences to a few keystrokes, hence the term "shortcut".
Some keyboard shortcuts require the user to press a single key or a sequence of keys one after the other. Other keyboard shortcuts require pressing and holding several keys simultaneously. For simultaneous keyboard shortcuts, one usually first holds down the modifier key(s), then quickly presses and releases the regular (non-modifier) key, and finally releases the modifier key(s). This distinction is important, as trying to press all the keys simultaneously will frequently either miss some of the modifier keys, or cause unwanted auto-repeat. One exception is shortcuts involving the Esc key, which almost always requires pressing and releasing the Esc key before pressing the next key.
Mnemonics are distinguishable from keyboard shortcuts. One difference between them is that the keyboard shortcuts are not localized on multi-language software but the mnemonics are generally localized to reflect the symbols and letters used in the specific locale.
When shortcuts are referred to as key bindings it carries the connotation that the shortcuts are customizable to a user's preference and that program functions may be 'bound' to a different set of keystrokes instead of or in addition to the default. This highlights a difference in philosophy regarding shortcuts. Some systems, typically end-user-oriented systems such as Windows or Macintosh consider standardized shortcuts essential to the environment's ease of use. These systems usually limit a user's ability to change shortcuts, typically requiring a separate, possibly third-party, utility to perform the task.
Other systems, typically Unix and related, consider shortcuts to be a user's prerogative, and that they should be changeable to suit individual preference. In most real-world environments, both philosophies co-exist; a core set of 'sacred' shortcuts remain fixed while others, typically involving an otherwise unused modifier key or keys, are under the user's control.