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21.9. Terminal Menu Editing During Boot

Menu entries can be modified and arguments passed to the kernel on boot. This is done using the menu entry editor interface, which is triggered when pressing the e key on a selected menu entry in the boot loader menu. The Esc key discards any changes and reloads the standard menu interface. The c key loads the command line interface.
The command line interface is the most basic GRUB interface, but it is also the one that grants the most control. The command line makes it possible to type any relevant GRUB commands followed by the Enter key to execute them. This interface features some advanced features similar to shell, including Tab key completion based on context, and Ctrl+a to move to the beginning of a line and Ctrl+e to move to the end of a line. In addition, the arrow, Home, End, and Delete keys work as they do in the bash shell.

21.9.1. Booting to Rescue Mode

Rescue mode provides a convenient single-user environment and allows you to repair your system in situations when it is unable to complete a normal booting process. In rescue mode, the system attempts to mount all local file systems and start some important system services, but it does not activate network interfaces or allow more users to be logged into the system at the same time. In Fedora, rescue mode is equivalent to single user mode and requires the root password.
  1. To enter rescue mode during boot, on the GRUB 2 boot screen, press the e key for edit.
  2. Add the following parameter at the end of the linux line on 64-Bit IBM Power Series, the linux16 line on x86-64 BIOS-based systems, or the linuxefi line on UEFI systems:
    systemd.unit=rescue.target
    Press Ctrl+a and Ctrl+e to jump to the start and end of the line, respectively. On some systems, Home and End might also work.
    Note that equivalent parameters, 1, s, and single, can be passed to the kernel as well.
  3. Press Ctrl+x to boot the system with the parameter.