GRUB Menu Configuration File | Official Red Hat Linux Administrators Guide

The configuration file, which is used to create the list in GRUB’s menu interface of operating systems to boot, essentially allows the user to select a preset group of commands to execute. The commands given in the previous “GRUB Commands” section of this chapter can be used, as well as some special commands that are available only in the configuration file.

Special Configuration File Commands

The following commands can be used only in the GRUB menu configuration file:

color normal-color selected-color — Configures specific colors for the foreground and background of the GRUB menu. Use simple color names, such as red/black. For example:
```
 color red/black green/blue.
```
default title-name — The default entry title name that will be loaded if the menu interface times out.
fallback title-name — If used, the entry title name to try if first attempt fails.
hiddenmenu — If used, prevents the GRUB menu interface from being displayed, loading the default entry when the timeout period expires. The user can see the standard GRUB menu by pressing the Esc key.
password password — If used, prevents the user who does not know the password from editing the entries for this menu option. Optionally, it is possible to specify an alternate menu configuration file after the password, so that, if the password is known, GRUB will restart the second stage of the boot loader and use this alternate configuration file to build the menu. If this alternate file were left out of the command, then a user who knows the password would be able to edit the current configuration file.
timeout — If used, sets the interval, in seconds, before GRUB loads the entry designated by the default command.
splashimage — Specifies the location of the splash screen image to be used when GRUB boots.
title — Sets a title to be used with a particular group of commands used to load an operating system. The # character can be used to place comments in the menu configuration file.

Configuration File Structure

The GRUB menu interface’s configuration file is /boot/grub/grub.conf. The commands to set the global preferences for the menu interface are placed at the top of the file, followed by the different entries for each of the operating systems or kernels listed in the menu. A very basic GRUB menu configuration file designed to boot either Red Hat Linux or Microsoft Windows 2000 might look as follows:

default=0 timeout=10 splashimage=(hd0,0)/grub/splash.xpm.gz # section to load linux title Red Hat Linux (2.4.18-5.47)                 root (hd0,0)                 kernel /vmlinuz-2.4.18-5.47 ro root=/dev/sda2                 initrd /initrd-2.4.18-5.47.img # section to load Windows 2000 title windows                 rootnoverify (hd0,0)                 chainloader +1

This file would tell GRUB to build a menu with Red Hat Linux as the default operating system, set to autoboot it after 10 seconds. Two sections are given, one for each operating system entry, with commands specific to this system’s disk partition table.

Note

The default is specified as a number. This refers to the first title line GRUB comes across. If you want Windows to be the default, change the default= value to 1.