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Changing Default OS

Use this guide if you have multiple partitions and operating systems on your computer and want to change the default operating system that will boot up when you turn on your computer. This guide applies only to systems using grub (aka grub legacy, where menu.lst exists) and not grub-pc (aka grub2, where menu.lst doesn't exist).

The StartUpManager can be used as a graphical alternative to the method described here.

Back Up Grub Settings

Copy this line into the terminal and press enter, it will back up your menu.lst and you can use the backup to restore your default settings.

sudo cp /boot/grub/menu.lst /boot/grub/menu.lst_backup

Open in a Text Editor

Edit the menu.lst file with one of the following commands (depending on what version of Ubuntu you're using):

Ubuntu

gksudo gedit /boot/grub/menu.lst

Kubuntu

kdesu kate /boot/grub/menu.lst

Xubuntu

gksudo mousepad /boot/grub/menu.lst

Finding the Line

## default num
# Set the default entry to the entry number NUM. Numbering starts from 0, and
# the entry number 0 is the default if the command is not used.
...
default     0
...

title      Ubuntu, kernel 2.6.15-27-amd64-generic
...
title      Ubuntu, memtest86+
...
title      Other operating systems:
...
title      Microsoft Windows XP Home

...you would change the number to 3. It is important to note that each lines such as "Other Operating Systems" should be counted as well.

Comments

Warbo: Yes, that's what I have been telling people to do ("put the non-Ubuntu OS which they would prefer to be default... above the "Automagic kernels" comment"). This is not something I do myself, because I only run Ubuntu and don't apply kernel updates (if you want to see how messed up my boot setup is then look at BootFromUSB Smile :) )

PatrickSchulz: Ooops! I just read the "...selected OS the default, but I have forgotten them :)". Sorry mea culpa... Next time I drop the tomatoes from my eyes before posting Wink ;-)

Ateo: My menu.lst has the comment

 ### BEGIN AUTOMAGIC KERNELS LIST

and not

 ### BEGIN AUTOMATIC KERNELS LIST

A very subtle type that had me searching for about 10 minutes.

Kevin Valentine: I was just forwarding this link to a grub newbie because he wants to make Windows his default boot entry. It's normally the last entry. Instead of having him cut and paste large chunks of text around, I told to additionally set updatedefaultentry=true. The default value is automagically updated when new kernels are added.


How to change the default boot order in Ubuntu 10.10:

Step 1) Open a terminal window. ...

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GrubHowto/ChangeDefaultOS (last edited 2017-09-03 15:58:02 by ckimes)