On 08/14/2016 05:50 AM, Peter Olson wrote:
>> On August 14, 2016 at 5:31 AM Arnt Karlsen <arnt@???> wrote:
>
> [...]
>
>> ..one neat thing about grub, is its shell, once you get the menu,
>> hit "e" and then the tab key twice, and play around to familiarize
>> yourselves with how it works, e.g how it finds disks, files, and
>> how you can boot into root's shell with e.g. "init=/bin/bash".
>
> My own experience with Grub has been less than "neat".
>
> But maybe that is because the times I have experienced Grub, my machine has been broken and I have been desperate to fix it. As far as I can tell, Grub has no help built in. You have to be an expert to use it.
>
> What does "e" plus tab key twice do?
>
> Is there some way I could try this on a system which boots successfully to find out about this?
>
> Peter Olson
> _______________________________________________

I had the good fortune to attend a presentation at a LUG meeting on using
the grub shell soon after I started using linux, and before I actually
needed it. I love the grub shell (except when I hate it.) Booting a
working system manually is good practice.

e lets you edit the highlighted menu entry.
c just drops you to a grub prompt.
TAB complete works
TAB TAB for help.

This, or some slight variation of it, usually works to boot an
installation on the first partition of the first hard disk:

c
set root=(hd0,1)
linux /vmlinuz ro root=/dev/sda1
initrd /initrd.img
boot

Here's a pretty good guide for booting from the grub shell.
https://www.linux.com/learn/how-rescue-non-booting-grub-2-linux

-fsr