The Linux Danish HOWTO: Keyboard setup

2. Keyboard setup

2.1 Loading a Danish key-table

You have two tools for configuring your keyboard. Under plain Linux you need loadkeys and under X11 you need xmodmap

To try out loadkeys try typing one of these two commands:


loadkeys /usr/lib/kbd/keytables/dk.map 
loadkeys /usr/lib/kbd/keytables/dk-latin1.map

The difference between the two lines is that dk-latin1.map uses `dead' keys while dk.map doesn't. Dead keys are explained in the section on dead keys. The program loadkeys and the keytables are part of the package kbd-0.90.tar.gz which (with differing version numbers) is available with all Linux distributions.

Usually loadkeys is run at boot-time from one of the scripts in the directory /etc/rc.d/. Details vary widely between distributions but it's a good idea to look for a file called rc.keymap.

(Note for non-Danish users: Support for other languages is enabled similarly. Use es.map for Spanish keyboards etc.)

X11 will to the largest possible extent follow the keymap used by plain Linux, but you can modify keyboard behavior under X11 with xmodmap. Usually the X11 initialization process will run this command atuomatically if you have a file called .Xmodmap in your home directory.

2.2 Getting the `AltGr` key to work under X

Edit the file /etc/Xconfig (under XFree86 2.0) or /etc/X11/XF86Config or /etc/XF86Config (under XFree86 3.x) and make sure the line


RightAlt    ModeShift

appears in the Keyboard section. Usually you can do this by uncommenting the appropriate line.

2.3 Dead keys and accented characters

Dead keys are those who don't type anything until you hit another key. Tildes and umlauts are like this by default under plain Linux if you use the dk-latin1.map key map. This is the default behaviour under Microsoft Windows as well.

Removing dead key functionality

Under plain Linux log on as root and type


loadkeys dk.map

Invoking dead key functionality

Invoking dead key functionality under plain Linux
Under plain Linux log on as root and type
loadkeys dk-latin1.map
Invoking dead key functionality under X11R5 sessions
Insert the following lines in a file ~/.Xmodmap or /etc/X11/Xmodmap
keycode 21 = acute Dgrave_accent bar keycode 35 = Ddiaeresis Dcircumflex_accent Dtilde
You can now make the dead keys work by typing (e.g.) xmodmap ~/.Xmodmap. Mostly this command will be issued automatically when you start up X. Do not follow this procedure if you use X11R6.

(Note for non-Danish readers: You can find the relevant key-codes for your own keyboard by using xev - it displays a little window and prints out all events it sees including key-codes for use with xmodmap.)
Invoking dead key functionality under X11R6 sessions
First you must make sure you are running XFree86 v3.1.2 or higher. Download and install everything related to this release if you have a lower version number. Dead keys won't work in X11R6 applications unless these were compiled with support for this input method. A useful example of such an application is emacs version 19.30 (or higher) or the version of xterm available at ftp://ftp.x.org/contrib/applications/ as xterm-R6-sb_right-ansi-3d.tar.gz.

Next you'll have to map some key to Compose or (equivalently) Multi_Key. The Scroll Lock key is most likely already mapped thus (you can verify this with xev,) and you can easily map the right Control key by uncommenting the appropriate line in the XFree86 configuration file (often /etc/XF86Config). If you wish to use some other key you should put something like
keycode 96 = Multi_key
in your ~/.Xmodmap file.

Finally make sure your shell and/or application is set up for iso-latin-1 compatibility as described in section on specific applications and you should be all set. You can e.g. get ã by typing Compose - a - ~. And if dead keys work under plain Linux they ought also to work under X11 now. The available keystroke combinations are listed in /etc/X11/locale/iso8859-1/Compose.

Many X applications do not support this general input method. Eventually this situation might improve, but until then you can either hack your applications or submit polite bug reports to their authors. The latter method is often the most efficient.

2.4 Making `ø` (oslash) `Ø` (Oslash) and `$` (the dollar sign) work

The dollar sign

In older versions of loadkeys there's a bug causing the dollar sign to be accessed with Shift-4 instead of AltGr-4 by default. You can fix this by changing the line


keycode   5 = four             dollar           dollar

in the keymap file to e.g.


keycode   5 = four             asciicircum      dollar

It doesn't matter if you use something else instead of asciicircum if it is a valid symbol name. See section on characters you can display under Linux for a list of valid symbols.

A similar bug appears in some versions of XFree86 and can be fixed by adding


keycode  13 = 4 dollar dollar

to your ~/.Xmodmap or /etc/X11/Xmodmap file.

`ø` (oslash) and `Ø` (Oslash)

On some older distributions ø and Ø appear as a cent and a Yen sign. If you have this problem determine what keymap you load at boot-up. You should be able to find out by looking around in the directory /etc/rc.d/ or simply by paying attention to what happens at boot-up. On my computer the keymap is called /usr/lib/kbd/keytables/dk-latin1.map. Find the line for keycode 40 in this file and change it from


keycode  40 = cent              yen


keycode  40 = oslash            Ooblique

and load the keytable as described in section on loading keytables.

Note: This bug appears to have been fixed in version 0.88 of the international keytable package.