Send keys when the VirtualBox guest has no sensible way of communicating with the outside world like SSH, for example in the EFI shell or before the OS is installed.
source scancodes.sh - loads functions from script
sendkeys - read VM name; read a string of ASCII characters and send them as scancodes to the guest virtual machine
sendspecial - read VM name; read the names of special characters by name, space delimited
sendenter - read VM name; send ENTER key
printksc - print names of recognized special keys