Alt key

The Alt key is a key on PC keyboards and is usually located to the left of the spacebar. The name comes from the Old English vocabulary and is short for alternate ( " change "); in German the abbreviation can also be understood as " alternative". With the Alt key can activate an additional function of these other key while pressing another key.

Functions

The Alt key is similar in its manner of use of the Shift key ( also: shift key or shift-key English: shift " the layer, change layer" ), enabling both this and the Ctrl key an extra level of keyboard layout.

The Alt key is usually not operated alone, but is only effective in combination with another key. Exceptions to this can be found among others in computer games or to activate the menu bar at CUA compliant systems such as Windows or OS / 2

On Unix systems with X11 Alt is occupied as a Meta key and usually triggers the modifiers Mod1, which triggers such as Windows menu items and frequently used commands. On Apple keyboards for Macintosh use the Alt key corresponds to the local option or Option key. In many cases, this is marked with Alt.

The English PC keyboard has a second Alt key on the right side of the spacebar. In most non-English keyboards, as well as the German, this was in an Alt-Gr key ( alternate graphic ) rededicated to enter the necessary for most non -English languages, higher number of characters with the same number of existing keys.

Keyboard shortcuts

Known combinations with the alt key in common operating systems are as follows:

  • Alt Tab enables you to toggle between running programs (forward).
  • Alt Shift Tab enables you to toggle between running programs (reverse).
  • Alt F2 opens a Linux command line within the graphical user interface, eg to start an application.
  • Alt F4 closes the active program. If one is in Windows machines on the desktop, this combination opens the dialog box to shut down the device.

In these three functions, the Ctrl key is analogous for MDI child windows.

  • Alt Shift allows in programs under some Windows versions, changing the keyboard layout (country- specific keyboard layout ).
  • Ctrl Alt largely corresponds to the Alt Gr key.
  • Ctrl Alt Del: The so-called " death grip " leads on Windows (only up to Vista and not with network logon ) to the Task Manager, under DOS, the computer has rebooted without running programs to finish what could be accompanied by data loss or rarely also damage to hardware. Even among many, but not all Linux operating systems, this key combination is programmed so that the system reboots, it being, however, first shut down.
  • Ctrl Alt F1 to F12 selects the respective console (Unix, Multiuser DOS, DR -DOS).
  • Alt ←, Alt → is used to control a previously or subsequently selected page from the history (history) of browsers and file managers.
  • Alt ⌫ ( or Alt Backspace Delete key ): Undo the last action (Undo ).
  • Alt letter: Access Key ( in German about access key) or Hot Key ( lit. hot key): In a menu bar or a menu letters are a menu item highlighted, then you can select the menu item with the Alt key and the underlined letter without mouse click ( considered by many operating systems and applications). Examples: = Open File Alt D
  • Save Alt S = file

Old Code

On Windows ( and earlier MS -DOS), it is possible to enter characters by pressing the Alt key and while entering a number on the numeric keypad, even those that may not be on the currently selected keyboard layout available. This technique is called Alt- numpad input method or Old Code.

If you want to type a character such as the copyright symbol " © ", which is not available on the keyboard in the normal character set but is certainly present, it first searches for its code number. Since Windows in Germany usually the code page 850 is used, one finds in the character list for the number 184 (decimal, hex 0xB8 ). For the " © " you are so Alt key on the number pad of the keyboard, the number 184, and then lets go of the Alt key, the letter appears.

In this way, all the characters of the corresponding mapped code pages can be written - about Windows 1252 ( with a leading 0 for " ANSI" code pages under a graphical user interface ) and code page 850 ( without leading 0 for OEM code pages without the graphical interface in DOS boxes or under plain DOS). Common signs are in this respect currency symbols and accented or other special characters of individual languages, such as the ß of the German or the French ç.

In most programs, only code numbers from 0 to 255 can be entered. Is one larger one, so the rest of the modulus when divided by 256 256 is taken of it, this prevents you can enter complex characters, for example, from the Unicode U 0100 beyond, as these are not supported by all programs. Some programs, however (not least the character table itself) allow the entry of all Unicode characters in this way, where else any necessary prefix 0 is not a required here.

IBM Common User Access Multiple Document Interface Shutdown (computing) MS-DOS Codepage 850 Character Map Esc key Scroll lock 8 (number) 9 (number) 4 (number) 6 (number) 3 (number)
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