grub-editenv

Edit GRUB environment variables. More information: https://www.gnu.org/software/grub/manual/grub/grub.html.

• Set a default boot entry (Assuming the boot entry already exists):

grub-editenv /boot/grub/grubenv set default={{Ubuntu}}

• Display the current value of the timeout variable:

grub-editenv /boot/grub/grubenv list timeout

• Reset the saved_entry variable to the default:

grub-editenv /boot/grub/grubenv unset saved_entry

• Append "quiet splash" to the kernel command-line:

grub-editenv /boot/grub/grubenv list kernel_cmdline