grub rescue>

[kadlam]

I am running Ubuntu 11.04. Recently I updated grub but didn't notice this problem until I had to reboot. Now I go straight to the grub rescue> prompt. Most of the commands that I have read about return a "Unknown command" message. My guess is that during the boot process the proper boot loader path is screwed up. Now I need help on trying to get out of this mess.
Thanks,
k

[jackgreenking]

grub resume> set
prefix=(hd0,1)/grub
root=hd0,1
set root=hd0,1
set prefix=(hd0,1)/boot/grub
set
root=hd0,1
prefix=(hd0,1)/boot/grub
insmod /boot/grub/normal.mod
normal

this work for me but you should find where your grub installed

[yancek]

Most of the commands that I have read about return a "Unknown command" message.

If you are getting this message at the grub prompt, you are probably using commands for Grub legacy and not Grub2 which Ubuntu uses. Take a look at the Grub2 tutorial at the link below;

GRUB 2 bootloader - Full tutorial

GNU GRUB Manual 1.99

Section 14 of the Grub Manual contains commands. You might post more info on your setup. How many drives/partitions? Is Ubuntu the only operating system? If not what else do you have? The command not found also happens when you try to run a command that requires root privileges and you don't prefix the command with sudo.

If you have the Ubuntu CD, boot it and open a terminal and enter this command: sudo fdisk -l(lower case Letter L in the command). It will show your partition information.

[kadlam]

First of all, thank you both - yancek and jackgreenking - for your responses. For now, I will respond to yancek as I think there are fundamental issues here that ARE likely addressed in the recommended documents.

[QUOTE=yancek;859860... Take a look at the Grub2 tutorial at the link below;]

I downloaded both and am studying them now.

[Section 14 of the Grub Manual contains commands.]

Judging by what I read in Section 14, grub has not loaded correctly in that apparently the only commands that work are insmod, ls, set and unset.

[You might post more info on your setup. How many drives/partitions?]
This is curious to me. Here's the command line activity:

grub rescue> ls
(hd0) (hd0,msdos5) (hd0,msdos1) (fd0)

I don't understand why there are four entities listed and, except for the fact this used to be a windows machine, do not understand the reference to msdos.


[Is Ubuntu the only operating system? If not what else do you have?]
As far as I know, the windows os was wiped clean when I originally loaded Ubuntu 10 more than a year ago and subsequently wiped everything out again when I loaed Ubunto 11.04. Perhaps this is not the case but I don't know what to do about it yet.

[The command not found also happens when you try to run a command that requires root privileges and you don't prefix the command with sudo.]
tyring to use sudo gets the respons, "Unknown command 'sudo'

[If you have the Ubuntu CD, boot it and open a terminal and enter this command: sudo fdisk -l]

Here's an abbreviated version of the printout with what I think is the relevent information;

Disk /dev/sda: 80,0 GB, 80000000000 bytes
.
.
Device Boot ... System
/dev/sda1 * Linux
/dev/sda2 Extended
/dev/sda5 Linux Swap / Solaris

While I'm running off the Ubuntu CD I'll go to Synaptic Package Manager and load the grub package listed. Done. Now Im going to try re-booting without the disk. ... and...
back to sqaure one:
grub rescue>

k

[yancek]

I don't understand why there are four entities listed and, except for the fact this used to be a windows machine, do not understand the reference to msdos.

The (hd0) refers to the physical hard drive. The other two refer to sda1 (Ubuntu) and sda5 (swap). The msdos thing is there for any entry, windows or Linux. I don't know why they do that.

The sudo command is only used from a Linux terminal and you will get a command not found from a grub prompt.

Read Section 13 at the link below to reinstall Grub2:

Grub 2 Basics - Ubuntu Forums

[kadlam]

Read Section 13 at the link below to reinstall Grub2: Grub 2 Basics - Ubuntu Forums

OK, thank you for that. I re-installed grub as instructed and now, during the boot process, I can hold down the shift key until I get a menu with options (none of which help (see below) and then type C to get to a grub> prompt.

If I let the boot process just do its thing, I get a white screen with non-decipherable text-like images. In the past I have tried tapping on the shift key while booting and inevitably - after several attempts - I will arrive at the normal ubuntu desktop screen. This problem may not be related to the original subject of this thread so I may post as another topic: Problem during boot - Ubuntu... or something like that. Any suggestions?

[yancek]

Take a look at Section 5 in the Ubuntu Grub2 link below to see if there is anything helpful:

https://help.ubuntu.com/community/Grub2

[kadlam]

Take a look at Section 5 in the Ubuntu Grub2 link below

Finally had a chance to follow up on your suggestion and it seems to have paid off. Here's what I did. Instead of going directly to section 5 of the Grub2 document, I stopped by section 4 and learned about start-up manager which, as it turned out, was nice to know about but not all that useful to me at this time. In the process of reading however, I also explored /etc/default/grub and decided to make a small tweak by uncommenting

# Uncomment to get a beep at grub start
GRUB_INIT_TUNE="480 440 1"

Then, after editing grub,

sudo update-grub

The update may have been what did the trick because now I am experiencing normal boot behavior. And once again, I've made a relatively simple problem complicated and learned a bunch in the process of finding a solution.

Thanks for the help yancek.

k