xmodmap is a utility for modifying keymaps and pointer button mappings in Xorg.
xmodmap is not directly related to XKB, it uses different (pre-XKB) ideas on how keycodes are processed within Xorg. Generally it is not recommended to use xmodmap, except maybe for the simplest tasks. See X KeyBoard extension if you have special demands on layout configuration.
On a Linux system using Xorg, there are two types of keyboard values: keycodes and keysyms.
- The keycode is the numeric representation received by the Linux kernel when a keyboard key or a mouse button is pressed.
- The keysym is the value assigned to the keycode. For example, when you press the
Akey on the keyboard, it generates keycode
73is mapped to the keysym
0×61which corresponds to the letter
ain the ASCII table.
- The keysyms are managed by Xorg in a table of keycodes defining the keycode-keysym relations which is called the keymap table. The command
xmodmapcan be used to show/modify that key table.
Optionally, install alsowhich provides a graphical front-end to xmodmap.
Print the current keymap table formatted into expressions:
$ xmodmap -pke
keycode 57 = n N
Each keycode is followed by the keysym it is mapped to. The above example indicates that the keycode
57 is mapped to the lowercase
n, while the uppercase
N is mapped to keycode
Each keysym column in the table corresponds to a particular combination of modifier keys:
Not all keysyms have to be set, but if you want to assign a latter keysym without assigning earlier ones, set them to
You can check which keycode corresponds to a key on your keyboard with the xev utility, see Extra Keyboard Keys#In Xorg for details.
XF86Mail. These keysyms can be found in
/usr/include/X11/XF86keysym.h. Many multimedia programs are designed to work with these keysyms out-of-the-box, without the need to configure any third-party application.
You can create your own map and store it in a configuration file in your home directory (i.e.
xmodmap -pke > ~/.Xmodmap
Make the desired changes to
~/.Xmodmap and then test the new configuration with:
Activate your custom table
If you are using GDM, XDM or KDM, there is no need to source your
~/.Xmodmap manually as these display managers source that file if it is present, whereas
startx does not. Therefore, to activate your custom table when starting Xorg, add the following:
if [ -s ~/.Xmodmap ]; then xmodmap ~/.Xmodmap fi
Alternatively, edit the global startup script
You can also make temporary changes for the current session. For example:
xmodmap -e "keycode 46 = l L l L lstroke Lstroke lstroke" xmodmap -e "keysym a = e E"
You can also also edit the keys:
Super (there always exists a left and a right one (Alt_R=AltGr)).
For example this can be useful if your right Control key is not working like your left one but you would like it to.
At first you have to delete/clear the signals that should be edited. In the beginning of your
!clear Shift !clear Lock clear Control !clear Mod1 !clear Mod2 !clear Mod3 clear Mod4 !clear Mod5 keycode 8 = ...
! is a comment so only
Mod4 (Standard: Super_L Super_R) get cleared.
Write the new signals at the end of
keycode 255 = !add Shift = Shift_L Shift_R !add Lock = Caps_Lock add Control = Super_L Super_R !add Mod1 = Alt_L Alt_R !add Mod2 = Mode_switch !add Mod3 = add Mod4 = Control_L Control_R !add Mod5 =
Super keys have now been exchanged with the
If you get the following error message
X Error of failed request: BadValue (integer parameter out of range for operation) it means the key you are trying to add is already in another modifier, so remove it using "remove MODIFIERNAME = KEYSYMNAME". Running
xmodmap gives you a list of modifiers and keys that are assigned to them.
The natural scrolling feature available in OS X Lion (mimicking smartphone or tablet scrolling) can be replicated with xmodmap. Since the synaptics driver uses the buttons 4/5/6/7 for up/down/left/right scrolling, you simply need to swap the order of how the buttons are declared in
~/.Xmodmap and append the following line to the file:
pointer = 1 2 3 5 4 7 6 8 9 10 11 12
Note how the 4 and 5 have been reversed.
Then update xmodmap:
To return to regular scrolling simply reverse the order of the 4 and 5 or delete the line altogether. For more information check Peter Hutterer's post, Natural scrolling in the synaptics driver, or the Reverse scrolling direction ala Mac OS X Lion? forum thread.
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