showkey

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  in-
       tended for debugging the keyboard driver or other low level interfaces.
       As such it shouldn't be of much interest to the regular end-user.  How-
       ever, some modern keyboards have keys or buttons that produce scancodes
       to which the kernel 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 number or each key pressed or released. The kind  of
       the  event,  press  or release, is also reported.  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 multiple 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 or-
       der 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 corre-
       sponds  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)

                                  1 Feb 1998                        SHOWKEY(1)