Changing default O.S. in grub

01-15-2006	#1 (permalink)
REDHATnardo Just Joined! Join Date: Oct 2005 Posts: 17	Changing default O.S. in grub Hello all, I have a dual boot setup using GRUB, currently windows XP is set to boot first. I would like to configure it so that RedHat boots by default. Any help would be greatly appreciated.

01-15-2006

#2 (permalink)

Nerderello

Linux Engineer

Join Date: Apr 2003

Location: North East England

Posts: 1,190

grub uses a configuration file called /boot/grub/grub.conf .

In this file you'll find (near the top) a line that read default= followed by a number (probably zero).

What you need to do is edit this file, as the root/super user, and change the default= number to be the number of the title that you want to load by default.

In English, that means that you will either logon as root, or open up a terminal/console window and type 'su -' followed by the root's password, and then type kedit, or gedit, or kate (ie. the name of a text editor).

You'll then open the /boot/grub/grub.conf file and notice that each operating system has an entry that starts with a 'title' line (starting to get the picture?). So, count (starting at zero, not one) the title line of the operating system (WinXP) that you want to be the default.

Example (taken from the tutorial area of this forum) :-

Here is the /boot/grub/grub.conf file :-

Code:

default=0
timeout=10
splashimage=(hd0,0)/grub/splash.xpm.gz
title Fedora Core 2 (2.6.5-1.358)
        root (hd0,0)
        kernel /vmlinuz-2.6.5-1.358 ro root=LABEL=/1 hda=38792,16,63
        initrd /initrd-2.6.5-1.358.img
title Mandrake 10.0
        root (hd0,0)
        kernel /vmlinuz-2.6.3-4mdk ro root=/dev/hda6 hda=38792,16,63
        initrd /initrd-2.6.3-4mdk.img
title Slackware
        root (hd0,4)
        kernel /boot/vmlinuz-ide-2.4.22 ro root=/dev/hda5 hda=38792,16,63
title BeOS
map (hd0) (hd2)
map (hd2) (hd0)
rootnoverify (hd2,4)
chainloader +1
title Windows 98 SE
map (hd0) (hd2)
map (hd2) (hd0)
rootnoverify (hd2,0)
makeactive
chainloader +1
title Fedora Core 1 (2.4.22-1.2188.nptl)
root (hd1,0)
kernel /boot/vmlinuz-2.4.22-1.2188.nptl ro root=/dev/hdc1
initrd /boot/initrd-2.4.22-1.2188.nptl.img

And we can see from this that the default operating system is zero (Fedora Core 2 (2.6.5-1.358 ).

To change it so that Windows boots by default I change the number in default to 4 (it's the fifth title, but we count starting at zero), like so :-

Code:

default=4
timeout=10
splashimage=(hd0,0)/grub/splash.xpm.gz
title Fedora Core 2 (2.6.5-1.358)
        root (hd0,0)
        kernel /vmlinuz-2.6.5-1.358 ro root=LABEL=/1 hda=38792,16,63
        initrd /initrd-2.6.5-1.358.img
title Mandrake 10.0
        root (hd0,0)
        kernel /vmlinuz-2.6.3-4mdk ro root=/dev/hda6 hda=38792,16,63
        initrd /initrd-2.6.3-4mdk.img
title Slackware
        root (hd0,4)
        kernel /boot/vmlinuz-ide-2.4.22 ro root=/dev/hda5 hda=38792,16,63
title BeOS
map (hd0) (hd2)
map (hd2) (hd0)
rootnoverify (hd2,4)
chainloader +1
title Windows 98 SE
map (hd0) (hd2)
map (hd2) (hd0)
rootnoverify (hd2,0)
makeactive
chainloader +1
title Fedora Core 1 (2.4.22-1.2188.nptl)
root (hd1,0)
kernel /boot/vmlinuz-2.4.22-1.2188.nptl ro root=/dev/hdc1
initrd /boot/initrd-2.4.22-1.2188.nptl.img

And there you have it.

have fun

Nerderello

__________________

Use Suse 10.1 and occasionally play with Kubuntu
Also have Windows 98SE and BeOS

01-17-2006	#3 (permalink)
REDHATnardo Just Joined! Join Date: Oct 2005 Posts: 17	Thanks a bunch. I should have looked a little more before I made a thread on it. I didn't realize that it was in the tutorials.

01-17-2006	#4 (permalink)
Nerderello Linux Engineer Join Date: Apr 2003 Location: North East England Posts: 1,190	no problems. There's some good stuff in the tutorials. Well worth a browse. Nerderello __________________ Use Suse 10.1 and occasionally play with Kubuntu Also have Windows 98SE and BeOS

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