keymaps(5) — Linux manual page


KEYMAPS(5)                   File Formats Manual                  KEYMAPS(5)

NAME         top

       keymaps - keyboard table descriptions for loadkeys and dumpkeys

DESCRIPTION         top

       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 (\).

INCLUDE FILES         top

       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

       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.

EXAMPLES         top

       (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"

SEE ALSO         top

       loadkeys(1), dumpkeys(1), showkey(1), xmodmap(1)

COLOPHON         top

       This page is part of the kbd (Linux keyboard tools) project.
       Information about the project can be found at 
       ⟨⟩.  If you have a bug report for this man‐
       ual page, send it to  This page was obtained
       from the project's upstream Git repository
       ⟨⟩ on 2020-06-09.  (At that time,
       the date of the most recent commit that was found in the repository
       was 2020-06-08.)  If you discover any rendering problems in this HTML
       version 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
       manual page), send a mail to

                                24 April 1998                     KEYMAPS(5)

Pages that refer to this page: dumpkeys(1)loadkeys(1)showkey(1)