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Re: New Grub user?

On Sat, 02 Oct 2004 03:31, Robert Harris wrote:
> I just installed my first system from the new Sarge installer (rather
> nice) and noticed I have Grub instead of lilo.  I've read the man
> pages and it's a bit different than I'm used to.  Does anyone have a
> very simple step by step to add a kernel (vmlinuz.old) so I can backup
> my current kernel then put a new one in /vmlinuz or something similar?
>  I need to put some new drivers in and really don't want to reinstall
> because I screwed up the kernel.  The Grub docs are a bit overwelming
> for my needs right now.

Actually installing the new kernel is nothing to do with Grub (maybe someone 
else here can advise you on how to do that).     In fact, AFAIK, the kernels 
don't care if you use GRUB or LILO (and GRUB / LILO don't care what kernel 
you're using, they'll boot anything you tell them to (well, almost).   

Editing GRUB to boot another kernel is actually quite simple:
All you need to do is add another entry in the /boot/grub/menu.lst file  
(which is _usually_ in the first partition of the first hard drive, unless 
Grub has been set to use a /boot/grub/menu.lst somewhere else).

menu.lst is a simple text file, you can add another entry with a text editor 
- just copy the existing entry and alter it as required.

Example from my menu.lst:

title           Debian GNU/Linux, kernel bf2.4   on  /hda1
root            (hd0,0)
kernel          /boot/vmlinuz-2.4.18-bf2.4 root=/dev/hda1 hdb=ide-scsi ro

title           Fedora Core 1 on /hda2
root            (hd0,1)
kernel          /boot/vmlinuz  root=/dev/hda2  hdb=ide-scsi  ro

'title' can be anything you like
'root' points GRUB at the partition your kernel is in  (in GRUB addressing 
terms which are drive no, partition no (starting at 0)
'kernel' points to your Linux kernel (or to a symlink) - the  'root' 
parameter on the 'kernel' line is passed to the Linux kernel so it 'knows' 
where it is and doesn't get a 'kernel panic' when it can't find itself.   

Read your menu.lst for what suits your installation.   Just keep the old file 
and you can always put it back if your new one screws up.   

If you have a GRUB boot floppy, make a note on paper of what your menu.lst 
says, then if all screws up you can get back in by floppy-booting GRUB, hit 
'c' (IIRC) to get the GRUB prompt, then type in by hand the 'root' and 
'kernel' lines followed by the command 'boot'.


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