Configuring the GRUB Bootloader

GRUB is a powerful bootloader that can be used to boot Linux, Windows, DOS, and other operating systems as well as the Xen virtualization system. By mastering its configuration file and command-line options, you can configure GRUB to boot exactly the way you want.

How Do I Do That?

GRUB is configured through the file /boot/grub/grub.conf; typical contents of this file look like this:

# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE:  You have a /boot partition.  This means that
#          all kernel and initrd paths are relative to /boot/, eg.
#          root (hd0,0)
#          kernel /vmlinuz-version ro root=/dev/main/root
#          initrd /initrd-version.img
#boot=/dev/hda
default=0
timeout=5
splashimage=(hd0,1)/grub/splash.xpm.gz
hiddenmenu
title Fedora Core (2.6.31-1.3420_fc6)
  root (hd0,1)
  kernel /vmlinuz-2.6.31-1.3420_fc6 ro root=/dev/main/root rhgb quiet
  initrd /initrd-2.6.31-1.3420_fc6.img
title Other
  rootnoverify (hd0,0)
  chainloader +1

This configuration file specifies two menu options, identified by the title keywords: Fedora Core and Windows (which Anaconda labels Other by default). Lines that start with a pound sign are comments. The first lines after the initial comments set up the appearance of the bootloader at startup time:

default= 0

Configures the first title entry as the default entry (they are numbered starting at 0)—in this case, Fedora Core.

timeout= 5

Sets the delay in seconds before the default ...

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