options] [console] [serial]
Specify a terminal for user interaction. This command is available only if GRUB was compiled with serial support. If both console and serial are specified, GRUB uses the first terminal where a key is pressed, or the first after the timeout has expired. If neither is specified, GRUB displays the current setting.
The terminal is a dumb terminal; if this option is not specified, the terminal is assumed to be VT100-compatible.
The terminal has num lines. The default is 24.
Suppress the prompt to hit any key (useful if your system does not have a terminal).
Specify the timeout in seconds.