Installation guide

Refer to Section 9.7, “GRUB Menu Configuration File” for more information on configuring
this interface.
Menu Entry Editor Interface
To access the menu entry editor, press the e key from the boot loader menu. The GRUB
commands for that entry are displayed here, and users may alter these command lines
before booting the operating system by adding a command line (o inserts a new line after
the current line and O inserts a new line before it), editing one (e), or deleting one (d).
After all changes are made, the b key executes the commands and boots the operating
system. The Esc key discards any changes and reloads the standard menu interface. The c
key loads the command line interface.
Note
For information about changing runlevels using the GRUB menu entry editor, refer to
Section 9.8, “ Changing Runlevels at Boot Time” .
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 shell-like features, including Tab key completion based on context, and Ctrl
key combinations when typing commands, such as 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.
Refer to Section 9.6, “ GRUB Commands” for a list of common commands.
9.5.1. Int erfaces Load Order
When GRUB loads its second stage boot loader, it first searches for its configuration file. Once
found, the menu interface bypass screen is displayed. If a key is pressed within three seconds, GRUB
builds a menu list and displays the menu interface. If no key is pressed, the default kernel entry in the
GRUB menu is used.
If the configuration file cannot be found, or if the configuration file is unreadable, GRUB loads the
command line interface, allowing the user to type commands to complete the boot process.
If the configuration file is not valid, GRUB prints out the error and asks for input. This helps the user
see precisely where the problem occurred. Pressing any key reloads the menu interface, where it is
then possible to edit the menu option and correct the problem based on the error reported by GRUB.
If the correction fails, GRUB reports an error and reloads the menu interface.
9.6. GRUB Commands
GRUB allows a number of useful commands in its command line interface. Some of the commands
accept options after their name; these options should be separated from the command and other
options on that line by space characters.
The following is a list of useful commands:
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