accessing the simplest grub prompt when booting from HD - Setup

This is a discussion on accessing the simplest grub prompt when booting from HD - Setup ; Hi all, I'm scratching my head on this one... When I start my computer, I'd like to have the grub prompt to show, and that's it. I don't have a floppy disk installed, so procedure to install grub on a ...

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Thread: accessing the simplest grub prompt when booting from HD

  1. accessing the simplest grub prompt when booting from HD

    Hi all,

    I'm scratching my head on this one...

    When I start my computer, I'd like to have the
    grub prompt to show, and that's it.

    I don't have a floppy disk installed, so procedure
    to install grub on a floppy disk don't work in my
    case.

    I don't care about having a menu allowing to
    choose between different OSes etc.

    All I want is the " grub> " prompt.

    And this " grub> " prompt should be installed on
    the hard disk's boot sector : that is, I want to
    have this grub prompt appear when I turn the
    computer on.

    The thing that really irritates me is that I got it
    working, once... And didn't write down the exact
    steps I took to make it work. Then I did a "fdisk /MBR"
    and erased that prompt. Now I can't manage to
    re-install that grub prompt.

    So here's my question : how can I, from a Knoppix
    bootable CD (Knoppix 4.01), install an "empty" grub
    on the first IDE hard-drive (/dev/hda) ?

    At the knoppix prompt I tried :

    # grub-install /dev/hda

    and it failed with "could not find device for /boot".


    Not that I don't want grub to boot from anything, I just
    want access to the " grub > " prompt.

    Any idea?

    Driss


  2. Re: accessing the simplest grub prompt when booting from HD

    On Thu, 19 Oct 2006 05:05:25 -0700, neuneudr wrote:

    > Hi all,
    >
    > I'm scratching my head on this one...
    >
    > When I start my computer, I'd like to have the
    > grub prompt to show, and that's it.
    >
    > I don't have a floppy disk installed, so procedure
    > to install grub on a floppy disk don't work in my
    > case.
    >
    > I don't care about having a menu allowing to
    > choose between different OSes etc.
    >
    > All I want is the " grub> " prompt.
    >
    > And this " grub> " prompt should be installed on
    > the hard disk's boot sector : that is, I want to
    > have this grub prompt appear when I turn the
    > computer on.
    >
    > The thing that really irritates me is that I got it
    > working, once... And didn't write down the exact
    > steps I took to make it work. Then I did a "fdisk /MBR"
    > and erased that prompt. Now I can't manage to
    > re-install that grub prompt.


    You probably don't want to use the MS-DOS loader to load GNU/Linux. The
    above fdisk sequence "broke" the loader.

    >
    > So here's my question : how can I, from a Knoppix bootable CD (Knoppix
    > 4.01), install an "empty" grub on the first IDE hard-drive (/dev/hda) ?
    >
    > At the knoppix prompt I tried :
    >
    > # grub-install /dev/hda
    >
    > and it failed with "could not find device for /boot".
    >
    >
    > Not that I don't want grub to boot from anything, I just want access to
    > the " grub > " prompt.
    >
    > Any idea?
    >
    > Driss
    >

    Note: comment inline.

    If grub is installed on the hard disk, it should display the menu. If you
    don't want any menu, remove the file menu.lst (or grub.conf, depending on
    the compile options used when grub was compiled.)

    I have limited experience with knoppix- it probably can do what you
    want, but I don't know what to do using that tool. But I have my own tool
    which is a simple bootable CD which allows the grub loader to be installed
    (or reinstalled). I explained where to get it and how to use it here:

    http://groups.google.com/group/comp....2040b59e1eac50

    The grub iso is less than 1M.

    --
    Douglas Mayne


  3. Re: accessing the simplest grub prompt when booting from HD

    > > Not that I don't want grub to boot from anything, I just want access to
    > > the " grub > " prompt.
    > >
    > > Any idea?
    > >
    > > Driss
    > >

    > Note: comment inline.
    >
    > If grub is installed on the hard disk, it should display the menu. If you
    > don't want any menu, remove the file menu.lst (or grub.conf, depending on
    > the compile options used when grub was compiled.)
    >
    > I have limited experience with knoppix- it probably can do what you
    > want, but I don't know what to do using that tool. But I have my own tool
    > which is a simple bootable CD which allows the grub loader to be installed
    > (or reinstalled). I explained where to get it and how to use it here:


    Hi there,

    thanks for your answer.

    The thing is : at one point I wanted to install grub though I had a
    Linux
    system without Grub installed. That system would boot fine *if* Grub
    was already on the hard disk.

    I managed to do two times what I wanted : just get the grub> prompt,
    but I still don't understand very well what I did.

    bah... No big deal.

    Thanks again,

    Driss


  4. Re: accessing the simplest grub prompt when booting from HD

    On Wed, 25 Oct 2006 15:42:15 -0700, neuneudr wrote:

    >> > Not that I don't want grub to boot from anything, I just want access to
    >> > the " grub > " prompt.
    >> >
    >> > Any idea?
    >> >
    >> > Driss
    >> >

    >> Note: comment inline.
    >>
    >> If grub is installed on the hard disk, it should display the menu. If you
    >> don't want any menu, remove the file menu.lst (or grub.conf, depending on
    >> the compile options used when grub was compiled.)
    >>
    >> I have limited experience with knoppix- it probably can do what you
    >> want, but I don't know what to do using that tool. But I have my own tool
    >> which is a simple bootable CD which allows the grub loader to be installed
    >> (or reinstalled). I explained where to get it and how to use it here:

    >
    > Hi there,
    >
    > thanks for your answer.
    >
    > The thing is : at one point I wanted to install grub though I had a
    > Linux
    > system without Grub installed. That system would boot fine *if* Grub
    > was already on the hard disk.
    >
    > I managed to do two times what I wanted : just get the grub> prompt,
    > but I still don't understand very well what I did.
    >
    > bah... No big deal.
    >
    > Thanks again,
    >
    > Driss
    >

    The boot loader is a fundamental concept of operating systems. The
    function that the loader provides may go unnoticed, especially if your
    computer arrived with the OS preinstalled, and the boot loader is
    functioning correctly. Even when you first install GNU/Linux, you may not
    have noticed that the loader was changed. That is because a lot of the new
    setup programs hide complexities from the end user in the name of
    "user-friendliness." IMO, they may not be doing you any favors. It is
    better to understand this concept from the start. That way, if you
    "break" the loader, you'll be in a better position to understand what
    needs to be done to fix it. The idea behind the loader isn't really that
    hard to understand. Take a few minutes to read the documentation. This
    looks like a good overview which supplements the official documentation:
    http://en.wikipedia.org/wiki/GRand_Unified_Bootloader

    Back to your original question...
    This screenshot shows the grub boot menu:
    http://www.xmission.com/~ddmayne2/10...2006-07-23.png

    If your grub loader is installed correctly, then it should display
    something similar for you. Notice the bottom of the screenshot which
    states:

    "...Press Enter to boot the selected OS, 'e' to edit the commands before
    booting, or 'c' for a command-line."

    Pressing 'c' will give direct access to the grub shell and its pre-boot
    environment. That may be what your original question was driving at.

    Also, when the loader cannot find its menu (because it absent), the
    default action is to go directly to the grub shell at boot:

    grub>

    --
    Douglas Mayne

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