Changing the default Boot OS in GRUB on Ubuntu 9.10

Ubuntu 9.10 ships with the new GRUB (Grand Unified Boot Loader 1.97 beta) in plain words its the software that boots the operating system you choose when you boot the computer. In earlier versions of Ubuntu / Grub to change the menu on the grub screen, one had to edit the /boot/grub/menu.lst file. In the new system this a little different from just editing the one file.

The GRUB configuration now resides at /boot/grub/menu.cfg But do not edit this file as it is generated from files from /etc/grub.d/* and /etc/default/grub.

And here is how to change the default operating system.

• First be root sudo su
• Edit the file /etc/default/grub
  The contents of the file would be like as shown below :
  

  # If you change this file, run 'update-grub' afterwards to update
  # /boot/grub/grub.cfg.
   
  GRUB_DEFAULT=3
  #GRUB_HIDDEN_TIMEOUT=0
  GRUB_HIDDEN_TIMEOUT_QUIET=true
  GRUB_TIMEOUT=10
  GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
  GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
  GRUB_CMDLINE_LINUX=""
   
  # Uncomment to disable graphical terminal (grub-pc only)
  #GRUB_TERMINAL=console
   
  # The resolution used on graphical terminal
  # note that you can use only modes which your graphic card supports via VBE
  # you can see them in real GRUB with the command `vbeinfo'
  #GRUB_GFXMODE=640x480
   
  # Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux
  #GRUB_DISABLE_LINUX_UUID=true
   
  # Uncomment to disable generation of recovery mode menu entrys
  #GRUB_DISABLE_LINUX_RECOVERY="true"

• Change the GRUB_DEFAULT value to number your default operating system
  Usually
  

  0 - Linux,
  1 - Linux,
  2 and 3 - Memtest,
  4 - Custom OS (Windows?)

  Change GRUB_TIMEOUT to change the default timeout if you want to.

• Run update-grub

root@digitalpbk# update-grub
Generating grub.cfg ...
Found linux image: /boot/vmlinuz-2.6.31-14-generic
Found initrd image: /boot/initrd.img-2.6.31-14-generic
Found memtest86+ image: /boot/memtest86+.bin
Found Microsoft Windows XP Home Edition on /dev/sda1
done

Reboot the system to verify your changes.

Happy Booting /p>

Note:

Although I found a built in command grub-set-default, It did not seem to do the job.

On /etc/grub.d Directory you can see many files named in the format XX_...where XX is a 2 digit number. The ones starting with 0 are not listed. Rest is starting from 1X, 2X, 3X etc.

• 1X_ would be your linux operating system
• 2X_ would be usually the memtest
• 3X_ would usually be your other Operating System, (Microsoft Windows? )

.

Found an easier way ? Please Share /p>