Change Boot Menu options from Grub Bootloader

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What is the Grub Bootloader?

Grub stands for (GRand Unified Bootloader)

The Grub bootloader is a package that is used to boot various operating systems via a menu upon computer system boot-up. The bootloader menu file usually resides in the /boot/grub/menu.lst file.


How the Grub Bootloader Works

Generally when most Linux systems are installed, the Grub bootloader program is installed. After Linux installation and computer reboot, the Grub bootloader menu should appear offering the user with a selection of operating systems to boot. The concept is similar to the boot.ini file that NTLDR (the boot loader for Windows OS) uses to supply a menu selection for a multiple-boot system.

When the computer system starts, the computer's BIOS locates and runs the bootstrap program on the MBR (Master Boot Record). A series of programs (of Grub) are run provide the user a selection of operating system to choose to boot into. For example, the user can select a version of Linux to load the Linux Kernel, or the user can select another operating system (like Windows) to load in the boot-loader (eg. NTLDR). This process of loading boot loaders for other operating systems than Linux is referred to as chainloading.


Why Edit the Grub Bootloader?

There are numerous reasons to edit the Grub bootloader:

  • Change the order of bootable operating systems in the menu list
  • Change the DEFAULT bootable operating system (eg. from timed count-down)
  • Change the DEFAULT count-down (timeout) value
  • Change the appearance (color) of the bootloader menu
  • Assign a boot password
  • Add additional options to the kernel upon loading Linux Kernel


NOTE: Many people complain that installing Linux causes Linux to be the DEFAULT operating system from a boot-loader list in Grub.
But the user can simply edit bootloader menu file to make their preferred operating system the DEFAULT.


Editing the Grub Bootloader

Let's assume that we have just installed Linux on our machine, and we want to edit the Grub Bootloader to set MS Windows as the DEFAULT operating system. !! NOTE: You should first make a backup copy of the bootloader file prior to making any editing changes. We will show you this in the step below !!


STEPS:


  1. Boot up into your Linux system.

  2. Open a command prompt (called a Linux shell) by selecting APPLICATIONS -> ACCESSORIES -> TERMINAL

  3. In the terminal, issue the command: sudo su (this will give administrator priviledges - assuming your have these priviledges, enter your account password)

  4. Issue the command: cp /boot/grub/menu.lst /boot/grub/menu.bk (just making a backup copy...)

  5. Issue the command: gedit /boot/grub/menu.lst (this opens the file in gedit application to allow you to make changes)

  6. Under Comments ## End Default Options ## lists the linux Kernel versions (in grouped sections containing title, uuid, kernel and initrd) that will boot up.
    The first grouping at the top of that list will be the DEFAULT.

  7. Farther below should list non-linux OS choices. Usually you can identify them because in the grouping will contain the keyword "chainloader"

  8. Copy and paste the non-linux (eg. Windows) group sections ABOVE the DEFAULT Linux grouped section)

  9. Save and exit the file.

  10. Test-out by rebooting your machine to load into your DEFAULT (Windows) OS, and then reboot to load into your Linux menu item.
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