KEYMAPS(5) File Formats Manual KEYMAPS(5)
keymaps - keyboard table descriptions for loadkeys and dumpkeys
These files are used by loadkeys(1) to modify the translation tables
used by the kernel keyboard driver and generated by dumpkeys(1) from
those translation tables.
The format of these files is vaguely similar to the one accepted by
xmodmap(1). The file consists of charset or key or string definition
lines interspersed with comments.
Comments are introduced with ! or # characters and continue to the
end of the line. Anything following one of these characters on that
line is ignored. Note that comments need not begin from column one as
with xmodmap(1).
The syntax of keymap files is line oriented; a complete definition
must fit on a single logical line. Logical lines can, however, be
split into multiple physical lines by ending each subline with the
backslash character (\).
A keymap can include other keymaps using the syntax
include "pathname"
A character set definition line is of the form:
charset "iso-8859-x"
It defines how following keysyms are to be interpreted. For example,
in iso-8859-1 the symbol mu (or micro) has code 0265, while in
iso-8859-7 the letter mu has code 0354.
Each complete key definition line is of the form:
keycode keynumber = keysym keysym keysym...
keynumber is the internal identification number of the key, roughly
equivalent to the scan code of it. keynumber can be given in
decimal, octal or hexadecimal notation. Octal is denoted by a
leading zero and hexadecimal by the prefix 0x.
Each of the keysyms represent keyboard actions, of which up to 256
can be bound to a single key. The actions available include
outputting character codes or character sequences, switching consoles
or keymaps, booting the machine etc. (The complete list can be
obtained from dumpkeys(1) by saying dumpkeys -l .)
Each keysym may be prefixed by a '+' (plus sign), in wich case this
keysym is treated as a "letter" and therefore affected by the
"CapsLock" the same way as by "Shift" (to be correct, the CapsLock
inverts the Shift state). The ASCII letters ('a'-'z' and 'A'-'Z')
are made CapsLock'able by default. If Shift+CapsLock should not
produce a lower case symbol, put lines like
keycode 30 = +a A
in the map file.
Which of the actions bound to a given key is taken when it is pressed
depends on what modifiers are in effect at that moment. The keyboard
driver supports 9 modifiers. These modifiers are labeled (completely
arbitrarily) Shift, AltGr, Control, Alt, ShiftL, ShiftR, CtrlL, CtrlR
and CapsShift. Each of these modifiers has an associated weight of
power of two according to the following table:
modifier weight
Shift 1
AltGr 2
Control 4
Alt 8
ShiftL 16
ShiftR 32
CtrlL 64
CtrlR 128
CapsShift 256
The effective action of a key is found out by adding up the weights
of all the modifiers in effect. By default, no modifiers are in
effect, so action number zero, i.e. the one in the first column in a
key definition line, is taken when the key is pressed or released.
When e.g. Shift and Alt modifiers are in effect, action number nine
(from the 10th column) is the effective one.
Changing the state of what modifiers are in effect can be achieved by
binding appropriate key actions to desired keys. For example, binding
the symbol Shift to a key sets the Shift modifier in effect when that
key is pressed and cancels the effect of that modifier when the key
is released. Binding AltGr_Lock to a key sets AltGr in effect when
the key is pressed and cancels the effect when the key is pressed
again. (By default Shift, AltGr, Control and Alt are bound to the
keys that bear a similar label; AltGr may denote the right Alt key.)
Note that you should be very careful when binding the modifier keys,
otherwise you can end up with an unusable keyboard mapping. If you
for example define a key to have Control in its first column and
leave the rest of the columns to be VoidSymbols, you're in trouble.
This is because pressing the key puts Control modifier in effect and
the following actions are looked up from the fifth column (see the
table above). So, when you release the key, the action from the fifth
column is taken. It has VoidSymbol in it, so nothing happens. This
means that the Control modifier is still in effect, although you have
released the key. Re-pressing and releasing the key has no effect.
To avoid this, you should always define all the columns to have the
same modifier symbol. There is a handy short-hand notation for this,
see below.
keysyms can be given in decimal, octal, hexadecimal, unicode or
symbolic notation. The numeric notations use the same format as with
keynumber. Unicode notation is "U+" followed by four hexadecimal
digits. The symbolic notation resembles that used by xmodmap(1).
Notable differences are the number symbols. The numeric symbols '0',
..., '9' of xmodmap(1) are replaced with the corresponding words
'zero', 'one', ... 'nine' to avoid confusion with the numeric
notation.
It should be noted that using numeric notation for the keysyms is
highly unportable as the key action numbers may vary from one kernel
version to another and the use of numeric notations is thus strongly
discouraged. They are intended to be used only when you know there is
a supported keyboard action in your kernel for which your current
version of loadkeys(1) has no symbolic name.
There is a number of short-hand notations to add readability and
reduce typing work and the probability of typing-errors.
First of all, you can give a map specification line, of the form
keymaps 0-2,4-5,8,12
to indicate that the lines of the keymap will not specify all 256
columns, but only the indicated ones. (In the example: only the
plain, Shift, AltGr, Control, Control+Shift, Alt and Control+Alt
maps, that is, 7 columns instead of 256.) When no such line is
given, the keymaps 0-M will be defined, where M+1 is the maximum num‐
ber of entries found in any definition line.
Next, you can leave off any trailing VoidSymbol entries from a key
definition line. VoidSymbol denotes a keyboard action which produces
no output and has no other effects either. For example, to define key
number 30 to output 'a' unshifted, 'A' when pressed with Shift and do
nothing when pressed with AltGr or other modifiers, you can write
keycode 30 = a A
instead of the more verbose
keycode 30 = a A VoidSymbol VoidSymbol \
VoidSymbol VoidSymbol VoidSymbol ...
For added convenience, you can usually get off with still more terse
definitions. If you enter a key definition line with only and exactly
one action code after the equals sign, it has a special meaning. If
the code (numeric or symbolic) is not an ASCII letter, it means the
code is implicitly replicated through all columns being defined. If,
on the other hand, the action code is an ASCII character in the range
'a', ..., 'z' or 'A', ..., 'Z' in the ASCII collating sequence, the
following definitions are made for the different modifier combina‐
tions, provided these are actually being defined. (The table lists
the two possible cases: either the single action code is a lower case
letter, denoted by 'x' or an upper case letter, denoted by 'Y'.)
modifier symbol
none x Y
Shift X y
AltGr x Y
Shift+AltGr X y
Control Control_x Control_y
Shift+Control Control_x Control_y
AltGr+Control Control_x Control_y
Shift+AltGr+Control Control_x Control_y
Alt Meta_x Meta_Y
Shift+Alt Meta_X Meta_y
AltGr+Alt Meta_x Meta_Y
Shift+AltGr+Alt Meta_X Meta_y
Control+Alt Meta_Control_x Meta_Control_y
Shift+Control+Alt Meta_Control_x Meta_Control_y
AltGr+Control+Alt Meta_Control_x Meta_Control_y
Shift+AltGr+Control+Alt Meta_Control_x Meta_Control_y
All the previous forms of key definition lines always define all the
M+1 possible modifier combinations being defined, whether the line
actually contains that many action codes or not. There is, however,
a variation of the definition syntax for defining only single actions
to a particular modifier combination of a key. This is especially
useful, if you load a keymap which doesn't match your needs in only
some modifier combinations, like AltGr+function keys. You can then
make a small local file redefining only those modifier combinations
and loading it after the main file. The syntax of this form is:
{ plain | <modifier sequence> } keycode keynumber = keysym
, e.g.,
plain keycode 14 = BackSpace
control alt keycode 83 = Boot
alt keycode 105 = Decr_Console
alt keycode 106 = Incr_Console
Using "plain" will define only the base entry of a key (i.e. the one
with no modifiers in effect) without affecting the bindings of other
modifier combinations of that key.
In addition to comments and key definition lines, a keymap can
contain string definitions. These are used to define what each
function key action code sends. The syntax of string definitions is:
string keysym = "text"
text can contain literal characters, octal character codes in the
format of backslash followed by up to three octal digits, and the
three escape sequences \n, \\, and \", for newline, backslash and
quote, respectively.
Then there may also be compose definitions. They have syntax
compose 'char' 'char' to 'char'
and describe how two bytes are combined to form a third one (when a
dead accent or compose key is used). This is used to get accented
letters and the like on a standard keyboard.
Various abbreviations can be used with kbd-0.96 and later.
strings as usual
Defines the usual values of the strings (but not the keys they
are bound to).
compose as usual for "iso-8859-1"
Defines the usual compose combinations.
To find out what keysyms there are available for use in keymaps, use
the command
dumpkeys --long-info
Unfortunately, there is currently no description of what each symbol
does. It has to be guessed from the name or figured out from the
kernel sources.
(Be careful to use a keymaps line, like the first line of `dumpkeys`,
or "keymaps 0-15" or so.)
The following entry exchanges the left Control key and the Caps Lock
key on the keyboard:
keycode 58 = Control
keycode 29 = Caps_Lock
Key number 58 is normally the Caps Lock key, and key number 29 is
normally the Control key.
The following entry sets the Shift and Caps Lock keys to behave more
nicely, like in older typewriters. That is, pressing Caps Lock key
once or more sets the keyboard in CapsLock state and pressing either
of the Shift keys releases it.
keycode 42 = Uncaps_Shift
keycode 54 = Uncaps_Shift
keycode 58 = Caps_On
The following entry sets the layout of the edit pad in the enhanced
keyboard to be more like that in the VT200 series terminals:
keycode 102 = Insert
keycode 104 = Remove
keycode 107 = Prior
shift keycode 107 = Scroll_Backward
keycode 110 = Find
keycode 111 = Select
control alt keycode 111 = Boot
control altgr keycode 111 = Boot
Here's an example to bind the string "du\ndf\n" to the key AltGr-D.
We use the "spare" action code F100 not normally bound to any key.
altgr keycode 32 = F100
string F100 = "du\ndf\n"
loadkeys(1), dumpkeys(1), showkey(1), xmodmap(1)
This page is part of the kbd (Linux keyboard tools) project.
Information about the project can be found at
⟨http://www.kbd-project.org/⟩. If you have a bug report for this man‐
ual page, send it to kbd@lists.altlinux.org. This page was obtained
from the project's upstream Git repository
⟨git://git.kernel.org/pub/scm/linux/kernel/git/legion/kbd.git⟩ on
2017-07-05. If you discover any rendering problems in this HTML ver‐
sion of the page, or you believe there is a better or more up-to-date
source for the page, or you have corrections or improvements to the
information in this COLOPHON (which is not part of the original man‐
ual page), send a mail to man-pages@man7.org
24 April 1998 KEYMAPS(5)
Pages that refer to this page: dumpkeys(1), loadkeys(1), showkey(1)