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user877329
Asked: 2014-10-20 01:03:35 +0800 CST

Identify which grub menu item used when booting

  • 772

Is it possible to test which menu item was used to start the system. If the choice of kernel was different i can for example do this in my login script

if uname -r | grep -q lowlatency; then
    jack-start
fi

But relying on kernel release seams ugly. I like to use the boot menu for such things is that I use the boot menu for choosing kernel/operating system anyway so doing more after startup takes more time.

Possible solutions i thought of other than using uname are

  • Set an environment variable when invoking the boot-menu entry. If this is possible is quite nice

  • I have configured grub to remember last used entry. Can I get what entry it was from somewhere? Yes, I found the file /boot/grub/grubenv

boot

2 Answers

  1. Best Answer

    Here is a solution I found:

    • The file /boot/grub/grubenv contains the name of the chosen entry

    So I can now use

    if grep -q 'Whatever' /boot/grub/grubenv; then
#   do stuff    
fi
    • 1

  2. Another way, using proc/cmdline, example:

    BOOT_IMAGE=/boot/vmlinuz-3.13.0-37-generic root=UUID=4c0c4c6d-708b-45b0-b9e9-a5e6a7de491e ro persistent quiet splash

    It's possible to use ~/.bashrc, to set a custom environment variable that it's value depends on proc/cmdline. As you can add a custom Linux boot parameter if you think /boot/vmlinuz-3.13.0-37-generic is not enough to identify it.

    Reference:

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