The GRUB rescue terminal is a safe mode for the Grand Unified Bootloader that assists users in booting an operating system so that permanent repairs can be made. Users can utilize the GRUB rescue mode to find and attempt repairs to boot images, kernels and root file systems.
The GRUB rescue terminal offers limited functionality to users, with a reduced set of commands.
Users can distinguish this mode from the regular GRUB interface by a "grub rescue>" prompt displayed on the computer screen.
Because changes made in the rescue mode are temporary, users can experiment without worry of breaking the GRUB configuration.