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SHOWKEY(1)                             General Commands Manual                            SHOWKEY(1)



NAME
       showkey - examine the codes sent by the keyboard

SYNOPSIS
       showkey [-h|--help] [-a|--ascii] [-s|--scancodes] [-k|--keycodes] [-V|--version]

DESCRIPTION
       showkey prints to standard output either the scan codes or the keycode or the `ascii' code of
       each key pressed.  In the first two modes the program runs  until  10  seconds  have  elapsed
       since  the  last  key  press  or  release event, or until it receives a suitable signal, like
       SIGTERM, from another process.  In `ascii' mode the program terminates when  the  user  types
       ^D.

       When  in scancode dump mode, showkey prints in hexadecimal format each byte received from the
       keyboard to the standard output. A new line is printed when an interval of about 0.1  seconds
       occurs  between the bytes received, or when the internal receive buffer fills up. This can be
       used to determine roughly, what byte sequences the keyboard sends at  once  on  a  given  key
       press.  The scan code dumping mode is primarily intended for debugging the keyboard driver or
       other low level interfaces. As such it shouldn't be of much interest to the regular end-user.
       However,  some modern keyboards have keys or buttons that produce scancodes to which the ker‐
       nel does not associate a keycode, and, after finding out what these are, the user can  assign
       keycodes with setkeycodes(8).

       When in the default keycode dump mode, showkey prints to the standard output the keycode num‐
       ber or each key pressed or released. The kind of the event, press or  release,  is  also  re‐
       ported.   Keycodes  are numbers assigned by the kernel to each individual physical key. Every
       key has always only one associated keycode number, whether the keyboard sends single or  mul‐
       tiple  scan codes when pressing it. Using showkey in this mode, you can find out what numbers
       to use in your personalized keymap files.

       When in `ascii' dump mode, showkey prints to the standard  output  the  decimal,  octal,  and
       hexadecimal value(s) of the key pressed, according to he present keymap.

OPTIONS
       -h --help
              showkey prints to the standard error output its version number, a compile option and a
              short usage message, then exits.

       -s --scancodes
              Starts showkey in scan code dump mode.

       -k --keycodes
              Starts showkey in keycode dump mode. This is the default, when no command line options
              are present.

       -a --ascii
              Starts showkey in `ascii' dump mode.

       -V --version
              showkey prints version number and exits.

2.6 KERNELS
       In 2.6 kernels key codes lie in the range 1-255, instead of 1-127.  Key codes larger than 127
       are returned as three bytes of which the low order 7 bits are: zero, bits 13-7, and bits  6-0
       of the key code.  The high order bits are: 0/1 for make/break, 1, 1.

       In  2.6  kernels  raw  mode,  or scancode mode, is not very raw at all.  Scan codes are first
       translated to key codes, and when scancodes are desired, the key codes are  translated  back.
       Various  transformations are involved, and there is no guarantee at all that the final result
       corresponds to what the keyboard hardware did send. So, if you want to know  the  scan  codes
       sent  by  various  keys it is better to boot a 2.4 kernel. Since 2.6.9 there also is the boot
       option atkbd.softraw=0 that tells the 2.6 kernel to return the actual scan codes.

SEE ALSO
       loadkeys(1), dumpkeys(1), keymaps(5), setkeycodes(8)



kbd                                          1 Feb 1998                                   SHOWKEY(1)