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Re: too many commands, "help" output rolls of screen

From: Andy Goth
Subject: Re: too many commands, "help" output rolls of screen
Date: Mon, 6 Oct 2008 17:00:58 -0500 (CDT)

address@hidden wrote:
> The top two lines of
> grub> help
> output will roll off the standard sized console. Please remove some
> commands so there aren't so many that they roll off the screen.

You should be able to remove testing commands (like "hello" and "play") from 
the build.  At the moment I don't have the ability to research how.

I recently found a related problem that I'll post more information on after 
doing some research.  It's the opposite issue: scrolling doesn't always happen 
when I want it to.
> P.S., What if I forget my password and I cannot login to my machine?

Presuming Linux, you can add "init=/bin/sh" to the kernel command line.  This 
will give you a shell without asking for a password.  From this shell you can 
edit your password file.

I sometimes use this trick to give myself an account. :^)  Seriously, if you 
don't password-protect your GRUB or LILO prompt (or anything else that edits 
the kernel command line), your system is open to anyone who has access to the 
keyboard.  Then again, unless you take extraordinary measures, your system is 
open to anyone with a screwdriver and physical access to the machine.

Warning 1: If support for your keyboard isn't compiled into the kernel, you 
won't be able to type, since the init scripts (which would load modules and do 
other configuration) will be bypassed.  I suggest using a PS/2 keyboard in this 

Warning 2: You won't have job control, so Ctrl-C and so on won't work.  Issue a 
command that takes a long time to complete, and you will have to wait.  Issue a 
command that never completes, and you will have to reboot.  I suggest running 
screen so as to give yourself a workaround.

Warning 3: The root filesystem might be mounted read-only.  Test this by using 
touch to create a file, then use ls to see if the file was created.  If not, 
type "mount" to get a listing of filesystems, then remount / with the device 
name taken from mount's output and the -oremount,rw option.  Or add "rw" to the 
kernel command line, removing "ro" if it is present.

Warning 4: Initrd scripts might change everything.

> Could you supply ed(1) in the commands perhaps?

I could be wrong, but I don't think grub was, is, or ever will be meant to 
modify filesystems.  Oh wait, I think it can be configured to remember the 
selected menu item as a new default, but I don't know how that's implemented.

Andy Goth |

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