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Grand Oxymore
Asked: 2010-11-22 03:29:41 +0800 CST

During a chroot attempt, I got this error: "chroot: failed to run command '/bin/bash': Exec format error"

  • 772

I was following the instructions of this tutorial HOWTO: Purge and Reinstall Grub 2 from the Live CD, when I encountered an error at step 1, as I launched the command

sudo chroot /mnt/temp

The error was the following:

chroot: failed to run command `/bin/bash': Exec format error

Where does that come from? How do I get through?

bash chroot

6 Answers

  1. Verify that you are using the right Live CD. For example, verify you are not using a 32bit CD instead of a 64bit CD. You need a 64bit kernel to run 64bit code, so check your architecture.

    Assuming you mounted your system to be chrooted in /media/sda1, to determine the architecture you can:

    ls /media/sda1/*

    if you see lib64 in the output, it's probably a 64bit system

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  2. I had the same problem when making an image for armhf arch. I had to install qemu-user-static and then copy it to chroot bin folder.

    sudo cp /usr/bin/qemu-arm-static /path/to/mount/usr/bin

    You may have to run

    systemctl restart systemd-binfmt.service

    then you should be able to chroot into the environment

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  3. The error means that your jail (/mnt/temp) does not contain a bash shell, or does not contain the libraries required to run the bash shell.

    If you created your jail using something like this:

    debootstrap --variant=buildd --arch i386 lucid /mnt/temp \
    http://archive.ubuntu.com/ubuntu/

    You probably meant to do this instead:

    debootstrap --variant=minbase --arch i386 lucid /mnt/temp \
    http://archive.ubuntu.com/ubuntu/

    However, as a technical answer to your problem, try:

    cp -r /bin /lib /mnt/temp

    This should allow you to chroot successfully, at which point you can do other things.

    There are about a million things wrong with doing that though, and almost certainly you do not want to do that. Use minbase when you create your jail, or install ubuntu on a blank target (eg. a virtual machine) and create a tar archive of the entire system which you then decompress into /mnt/temp.

    • 1

  4. Indeed this is a 64-bit 32-bit incompatibility.

    Although with 

    cp /bin/bash /mount/temp/tmp

    (copies 32-bit exec to the new root in the tmp directory

    chroot /mount/temp /tmp/bash

    chroot is fine, all commands still fail. You would have to copy them all over.

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  5. In my case, I was trying to chroot into a 64-bit version of Linux but my current Linux was 32-bit.

    I had mounted a disk image (master image, for replication on multiple machines).

    • -1

  6. I think in is a BUG.

    `/bin/bash'

    but not

    'bin/bash'

    • -2