Ubuntu – How to get grub2 to remember last choice

dual-bootgrub2

Grub2 – Community Ubuntu Documentation says the following:

Saving an OS can be achieved by running sudo grub-set-default if
DEFAULT=saved is set in /etc/default/grub. It may also be saved if
GRUB_SAVEDEFAULT=true is also set in /etc/default/grub. In this case,
the default OS remains until a new OS is manually selected from the
GRUB 2 menu or the grub-set-default command is executed.

I put the lines DEFAULT=saved AND GRUB_SAVEDEFAULT=true in /etc/default/grub, and ran sudo grub-set-default. Here is the output:

$ sudo grub-set-default
entry not specified.
Usage: grub-set-default [OPTION] entry
Set the default boot entry for GRUB.

  -h, --help              print this message and exit
  -v, --version           print the version information and exit
  --boot-directory=DIR    expect GRUB images under the directory DIR/grub
                          instead of the /boot/grub directory

ENTRY is a number or a menu item title.

Report bugs to <bug-grub@gnu.org>.

Am I not following the documentation correctly? What's the correct way to do this?

Best Answer

The documentation in this case is wrong. All variables in /etc/default/grub start with GRUB_, so it's GRUB_DEFAULT=saved, not DEFAULT=saved. I've corrected the Ubuntu wiki to reflect that.

The official grub manual describes this correctly: http://www.gnu.org/software/grub/manual/grub.html#Simple-configuration

Put the following in /etc/default/grub (command line: gedit admin:///etc/default/grub):

GRUB_DEFAULT=saved
GRUB_SAVEDEFAULT=true

Then run:

sudo update-grub
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