SHOWKEY(1) General Commands Manual SHOWKEY(1)
showkey - examine the codes sent by the keyboard
showkey [-h|--help] [-a|--ascii] [-s|--scancodes] [-k|--keycodes] [-V|--version]
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.
-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.
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.
loadkeys(1), dumpkeys(1), keymaps(5), setkeycodes(8)
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 firstname.lastname@example.org. This page was obtained from the project's upstream Git repository ⟨https://github.com/legionus/kbd.git⟩ on 2021-06-20. (At that time, the date of the most recent commit that was found in the repository was 2021-05-27.) 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 email@example.com kbd 1 Feb 1998 SHOWKEY(1)
Pages that refer to this page: loadkeys(1), keymaps(5), setkeycodes(8)