showkey - Unix, Linux Command
showkey - examine the codes sent by the keyboard
showkey [-h|--help] [-a|--ascii] [-s|--scancodes] [-k|--keycodes]
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 shouldnt 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
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
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.
showkey prints to the standard error output its version number, a compile
option and a short usage message, then exits.
showkey in scan code dump mode.
showkey in keycode dump mode. This is the default, when no command line options
showkey in ascii dump mode.