Provided by: kbd_2.3.0-3ubuntu4.22.04_amd64 

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
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 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)