showkey(1) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | 2.6 KERNELS | SEE ALSO | COLOPHON

SHOWKEY(1)               General Commands Manual              SHOWKEY(1)

NAME         top

       showkey - examine the codes sent by the keyboard

SYNOPSIS         top

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

DESCRIPTION         top

       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 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         top

       -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         top

       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         top

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

COLOPHON         top

       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
       manual page, send it to kbd@lists.altlinux.org.  This page was
       obtained from the project's upstream Git repository
       ⟨https://github.com/legionus/kbd.git⟩ on 2021-04-01.  (At that
       time, the date of the most recent commit that was found in the
       repository was 2021-03-03.)  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
       man-pages@man7.org

kbd                            1 Feb 1998                     SHOWKEY(1)

Pages that refer to this page: loadkeys(1)keymaps(5)setkeycodes(8)