KEYMAPS(5) Linux User's Manual KEYMAPS(5)NAMEkeymaps - keyboard table descriptions for loadkeys and dumpkeys
DESCRIPTION
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 char‐
acter (\).
INCLUDE FILES
A keymap can include other keymaps using the syntax
include "pathname"
CHARSET DEFINITIONS
A character set definition line is of the form:
charset <charset>
Where <charset> is one of the currently supported charsets, which can
be found using dumpkeys --help. 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.
COMPLETE KEYCODE DEFINITIONS
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
Latin1 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 which case this
keysym is treated as a "letter" and therefore affected by the "Cap‐
sLock" 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 Cap‐
sLock'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 8 modifiers. These modifiers are labeled (completely
arbitrarily) Shift, AltGr, Control, Alt, ShiftL, ShiftR, CtrlL and
CtrlR. 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
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 defini‐
tion 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 fol‐
lowing 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 sym‐
bol. There is a handy short-hand notation for this, see below.
keysyms can be given in decimal, octal, hexadecimal or symbolic nota‐
tion. The numeric notations use the same format as with keynumber. The
symbolic notation resembles that used by xmodmap(1). Notable differ‐
ences 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.
If you do need to use numeric notations, comment those lines heavily
and add a comment at the top of the file. This will save your sanity
(if any) later. If this file should happen to get past your personal
system, it may also save you much pain and embarrassment. Also, please
file a bug report against loadkeys noting the need for a 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 col‐
umns, 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 number of entries found
in any definition line.
Next, you can leave off any trailing VoidSymbol entries from a key def‐
inition line. VoidSymbol denotes a keyboard action which produces no
output and has no other effects either. For example, to define key num‐
ber 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 follow‐
ing definitions are made for the different modifier combinations, pro‐
vided these are actually being defined. (The table lists the two pos‐
sible 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
SINGLE MODIFIER DEFINITIONS
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 modi‐
fier 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.
STRING DEFINITIONS
In addition to comments and key definition lines, the keymap files 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 for‐
mat of backslash followed by up to three octal digits, and the three
escape sequences \n, \\, and \", for newline, backslash and quote,
respectively.
COMPOSE DEFINITIONS
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 let‐
ters and the like on a standard keyboard.
ABBREVIATIONS
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.
alt_is_meta
Whenever some combination is defined as an ASCII symbol, and
there is a corresponding Alt keymap, define by default the cor‐
responding Alt combination as Meta_value.
To find out what keysyms there are available for use in keymaps files,
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.
EXAMPLES
(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 nor‐
mally 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"
SEE ALSOloadkeys(1), dumpkeys(1), showkey(1), xmodmap(1).
Console tools 09 Oct 1997 KEYMAPS(5)
