Alt (key)

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The Alt key is a key on PC keyboards and is usually located to the left of the space bar . The term Alt comes from English and is a short form for alternate ("to change"); in German the abbreviation can also be understood as " alternative ". The Alt key can be used to activate an additional function of that other key while simultaneously pressing another key.

Functions

Control, Windows, Alt key.

The way the Alt key is used is similar to the Shift key (also: Shift key from English: shift "the shift, change level") and enables an additional level of keyboard assignment in addition to this and the Ctrl key .

The Alt key is usually not pressed alone, but only takes effect in conjunction with another key. Exceptions to this can be found in computer games or to activate the menu bar in CUA- compliant systems such as Windows or OS / 2 . The latter function usually also fulfills F10.

Alt or Option key on an Apple keyboard

On Unix and Unix -like systems with X11 , Alt is assigned as a meta key and usually triggers the Modifier Mod1 , which, like under Windows, triggers menu entries and frequently used commands. Under macOS , the Alt key corresponds to the option or option key , which is used to switch to the third-party assignment.

The English PC keyboard has a second Alt key on the right side of the space bar. Most non-English keyboards, including the German one, have been converted to an Alt-Gr key (alternate graphic) in order to be able to enter the higher number of characters required for most non-English languages ​​without significantly increasing the number of existing keys.

Keyboard shortcuts

Well-known combinations with the Alt key in popular operating systems are as follows:

  • Alt+ Tabenables switching between running programs (forward).
  • Alt+ Umschalt+ Taballows you to switch between running programs (backwards).
  • Alt+ F4closes the active program. If you are on the desktop with Windows computers or if you click on the taskbar beforehand , this combination opens the dialog box for shutting down the device, which also offers shutdown without installing updates .

With the three functions mentioned above, the Ctrl key behaves in the same way for MDI subwindows .

  • Alt+ F2under Linux opens a command line within the graphical user interface to e.g. B. to start an application.
  • Alt+ Umschaltenables the keyboard layout to be changed in programs under some Windows versions (country-specific keyboard layout).
  • Strg+ Altlargely corresponds to the key Alt Gr.
  • Strg+ Alt+ Entf: Under Windows (only up to Windows Vista and not with network logon ) the so-called “ grip ” leads to the task manager , under DOS the computer was restarted without closing any running programs, which could result in data loss or, rarely, damage to the hardware. Even on many, but not all, Linux operating systems, this key combination is programmed to restart the system, but to shut it down first .
  • Strg+ Alt+ F1to F12selects the respective console (Unix, Multiuser DOS, DR-DOS).
  • Alt+ , Alt+ is used to control a previously or later selected page from the history of browsers and file managers.
  • Alt+ (or Alt+ Rücklöschtaste): Undo the last action ( Undo ).
  • Alt+ Buchstabe: Access Key (in German about access key ) or Hot Key (literally hot key ):
    • If letters of a menu item are underlined in a menu bar or in a menu (often only visible after pressing Altor F10), the menu item can be selected with the Alt key and the underlined letter without a mouse click (applies to many operating systems and applications). To move around in the menus, the Alt key may be released, but not pressed down again. Examples:
      • Alt+ D= D atei menu open
      • Alt+ A= A iew menu open
    • The same applies to highlighted hyperlink letters in websites, although the type (or presence) of the highlighting is not uniformly regulated here. In most web browsers , such an “access key” in the website text even has priority over the same key combination in a menu of the web browser itself.
    • In most cases you have to press to see the underlines.
  • In Windows , Alt+ opens Leertastethe context menu of the active window (corresponds to a right-click on the title bar or a left-click on the icon). This is particularly useful if you then Vpress (Move) and an arrow key and then move the mouse; in this way, windows can be brought back onto the screen that are in a position outside the visible area.
  • Under KDE Plasma , Alt+ opens Leertastethe command line at the top of the screen, on which you can run any program (similar to the “Run” function under Windows with Win+ R).
  • Alt+ Druckonly takes a screenshot of the active window under Windows.
  • Alt+ Druck+ Buchstabesends commands directly to the kernel as magic S-Abf key on many Linux systems .

Alt code

Under Windows (and previously MS-DOS ) it is possible to enter characters by pressing the Alt key and simultaneously entering a number on the number pad, including characters that may not be available on the currently selected keyboard layout . This technique is called the alt-numpad input method, or alt-code.

If you want to enter a character such as the copyright symbol “©” that is not available on the keyboard but is definitely available in the normal character set, you first look for its code number. Since code page 850 is mostly used in Windows in Germany , the number 184 (decimal, hex 0xB8) can be found in the character table . For the “©”, hold down the Alt key and enter the number 184 in the numeric keypad and then release the Alt key, the character appears.

In this way, all characters of the appropriately mapped code pages can be written - for example Windows-1252 (with a prefixed 0 for "ANSI" code pages under a graphical user interface) and code page 850 (without a prefixed 0 for OEM code pages without a graphical user interface as in DOS- Boxes or under pure DOS). Common characters in this regard are currency symbols and accented or other special characters from individual languages such as the ß of German or the ç of French.

Most programs can only enter code numbers from 0 to 255. If you enter larger values , the modulo 256 is taken from it, i.e. the remainder when dividing by 256. However, some programs (not least the character table itself) allow the input of all Unicode characters in this way, with one otherwise necessary here leading 0 is not required.

Individual evidence

  1. "Access keys" in the official HTML specification (English)

Web links