Print keycodes, scancodes, or ASCII codes of keys pressed on the keyboard. The default is to show keycodes. In keycode and scancode mode, the program terminates 10 seconds after the last key is pressed. In ASCII mode, press Ctrl-D to exit. This command may not function properly under the X Window System, which also reads from the console device.
Print the ASCII character, decimal, octal, and hexadecimal values of keys pressed.
Print version number and help message, then exit.
Print keycodes associated with key-press events. This is the default mode.
Print the keyboard scancodes associated with key-press events.