grub question

[D. Hugh Redelmeier]

| From: Francois Ouellette <fouellet-cpI+UMyWUv9BDgjK7y7TUQ at public.gmane.org>

| What is the command-line grub command to re-install it to the boot sector
| with the chainloader to the Linux partition?
| 
| I accidentally wiped it with the Windoze installation disk and cannot 
| find the command to do it from the FC3 rescue disk.

What I do in this case is boot from a grub floppy, get it to load the
system (FC3?) and then ask FC3 to install the boot sector.

[Warning: this is all from my imperfect memory.]

Making a grub boot floppy isn't too hard, but it is arcane.  I keep
one lying around.  They don't go obsolete very quickly -- I think I
still use one I built from RHL8.  Here's how to get the documentation.

    info grub
    select "installation"
    select "Creating a GRUB boot floppy"

It says (among other things):

     # cd /usr/share/grub/i386-pc
     # dd if=stage1 of=/dev/fd0 bs=512 count=1
     1+0 records in
     1+0 records out
     # dd if=stage2 of=/dev/fd0 bs=512 seek=1
     153+1 records in
     153+1 records out

If you don't have a working linux, you can probably do this from
KNOPPIX.  You do have a KNOPPIX, don't you?

Once you have a working grub boot disk, boot it.  Then type the
commands into its prompt.
Note: I am assuming that FC3 is on the 4the partition; adjust
accordingly.
Note: Grub counts up from 0, so the first drive is hd0 and the 4th
partition is 3.

	root (hd0,3)
	configfile /boot/grub/grub.conf

[Note: grub is ridiculously powerful.  You can do a lot of things from
its command line.]

This should give you the normal FC3 bootup.  Once FC3 is running,
install grub on the master boot sector.  From a shell:

	grub-install /dev/hda

I also like to install it on the boot sector of my LINUX partition(s):

	grub-install /dev/hda4

That way I can have multiple linux installations and use chainloading
to select which partition to boot.  This has advantages when kernels
are subsequently updated.

Good luck,

Hugh Redelmeier
hugh-pmF8o41NoarQT0dZR+AlfA at public.gmane.org  voice: +1 416 482-8253
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