For a list of keyboard shortcuts, see Table of keyboard shortcuts
⌥ Opt or Alt The Alt key on a computer keyboard is used to change the function of other pressed
keys. Thus, the Alt key is a modifier key, used in a similar fashion to the Shift key.
For example, simply pressing "A" will type the letter a, but if you hold down either
Alt key while pressing A, the computer will perform an Alt+A function, which varies from
program to program. The international standard ISO/IEC 9995-2 calls it Alternate key. The
key is located either side of the Space bar, but in non-US PC keyboard layouts, rather
than a second Alt key, there is an 'Alt Gr' key to the right of the space bar. Both placements
are in accordance with ISO/IEC 9995-2. The standardized keyboard symbol for the Alt
key is given in ISO/IEC 9995-7 as symbol 25, and in ISO 7000 “Graphical symbols for use
on equipment” as symbol ISO-7000-2105. This symbol is encoded in Unicode as U+2387 alternative
key symbol. The Alt key should not be confused with the
Altmode key on some Teletypes and ASCII terminals, which is a synonym for the ASCII escape character.
Evolution The Alt key has come to replace the Meta key
of the old MIT keyboards. In their original function, both Alt and Meta would set the
high bit of the signal generated by the key to 1. However, in modern software, due to
the requirement of the high bit for internationalisation, Alt no longer works in such a way.
Since the 1990s Alt has been printed on the Option key on most Mac keyboards. Alt is used
in non-Mac software, such as Unix and Windows programs, but in OS X it is always referred
as Option key. Option key's behaviour in Mac OS X differs slightly from that of the Windows
Alt key. Alt key combinations
The Alt key is well known as part of the key combinations:
Ctrl+Alt+Delete brings up a task manager in some operating systems, see Control-Alt-Delete.
Alt+⌘ Cmd+Esc does this on Mac OS Ctrl+Alt+← Backspace usually causes the
X display server to shut down or to restart, see Control-Alt-Backspace.
Alt+F4 closes the current window on most windowing systems.
Alt+Tab ↹ switches between the currently opened windows on most windowing systems,
see Alt-Tab. Alt key for special characters
Windows In Microsoft Windows, holding down the Alt
key while typing in numbers on the numeric keypad allows the user to type special characters
not normally available on the keyboard. For example, holding down Alt while typing 0225
on the numeric keypad will result in á, the character at 225 in the codepage. These extended
keyboard characters are useful for persons using foreign languages, mathematics, currency
symbols, business use, etc. Some computers work the same if the Num Lock key is on.
Mac OS X On a Macintosh, the Alt key is called the
Option key. It is not used to enter numeric character codes. Instead, keyboard letters
and numbers are used. The diagram below shows the special characters a US Mac keyboard will
produce when the Option key is pressed.
The highlighted orange keys show the accents available from the combination of the Alt
key and the keyboard characters e i u and ` n. The accent then can be applied to associated
letters both lower and uppercase. The additional characters a Mac will produce are a combination
of both the ⌥ Option key and the ⇧ Shift key pressed down together. With this combination
pressed the keyboard will now produce a different set or an uppercase version of the previous
set in some cases.
Alt key clicked alone When a user clicks the Alt key by itself on
Microsoft Windows, that moves keyboard focus to the menubar of the application having keyboard
focus, and the key is not delivered to the application. In that state, another click
of the Alt key will be delivered to the application. On other platforms, for example Ubuntu, the
Alt key clicked by itself may invoke another application and not be delivered to the application
having keyboard focus. See also
Control-Alt-Delete Modifier key
Alt code Option key
References