The hidden menu interface
=========================
When your terminal is dumb or you request GRUB of hiding the menu
interface explicitly with the command `hiddenmenu' (Note:hiddenmenu), GRUB doesn't show the menu interface (Note:Menu
interface) and automatically boots the default entry, unless
interrupted by pressing <ESC>.
When you interrupt the timeout and your terminal is dumb, GRUB falls
back to the command-line interface (Note:Command-line interface).