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Knowledge Cube
Asked: 2011-10-16 17:18:42 +0800 CST

Is there a way to save the output of vbeinfo?

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I'm trying to correct some GRUB2 and Plymouth display problems in 11.10 as part of an ongoing saga. I'm going to run the vbeinfo command to check supported display modes, but unfortunately from what I can tell this command can only be run from GRUB2, and hence the output is only visible while the command is run in it.

I would like to keep a copy of the output for reference or sharing. Is it possible to save this output somewhere I can access it after logging in, and if so, how would I do it? Alternately, if it is not possible to save the output, then why not?

And because I know someone might answer with this: no, I do not have a camera handy to take a picture of my screen (besides my laptop's webcam, which is an awkward solution at best), and I would rather not write it all down on paper if I can help it.

grub2

4 Answers

  1. Best Answer

    Saving the output of vbeinfo will proof the be not possible without too much work.

    Fortunately you can also use hwinfo to list your VBE supported modes using the command sudo hwinfo --framebuffer in a terminal.

    Install hwinfo with the command sudo apt-get install hwinfo.

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  2. Grub2 doesnt allow you to save files - from a security point of view and for the reason to prevent corruption to the filesystem from an invalid grub configuration.

    The closest you can come to writing information from grub is to save the value of an environment variable which you can subsequently read from the running O/S.

    Thus, you can run vbeinfo and then create an environment variable containing the information you want to save.

    set myvar="some vbeinformation typed manually"
export myvar
save_env myvar

    In the running O/S the file /boot/grub/grubenv will have the environment variable that you have just saved.

    You could parse that file for your information. Perhaps easier use the following to list all saved variables.

    grub-editenv list

    This file - called the environment block is limited to 1024 characters.

    Use the following to reset the file:

    sudo grub-editenv create

    Note from this wiki:

    For safety reasons, this storage is only available when installed on a plain disk (no LVM or RAID), using a non-checksumming filesystem (no ZFS), and using BIOS or EFI functions (no ATA, USB or IEEE1275).

    From my testing - there is probably a bug lurking somewhere. It can take a couple of tries before the environment block is successfully written to.

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  3. Unfortunately it's unlikely you can save the output from vbeinfo as no file system has been mounted at this stage of the boot process for GRUB2 to save it to.

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  4. you can use the built in pager with:

    set pager=1
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