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 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 as-
signed by the kernel to each individual physical key. Every key has al-
ways only one associated keycode number, whether the keyboard sends sin-
gle 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 order
7 bits are: zero, bits 13-7, and bits 6-0 of the key code. The high or-
der 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.
AUTHORS
Andries Brouwer <aeb@cwi.nl>
SEE ALSO
loadkeys(1), dumpkeys(1), keymaps(5), setkeycodes(8)
kbd 1 Feb 1998 SHOWKEY(1)
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