grub-editenv

Set a default boot entry

$ grub-editenv /boot/grub/grubenv set default=Ubuntu

$ grub-editenv /boot/grub/grubenv list

$ grub-editenv /boot/grub/grubenv unset saved_entry

grub-editenv file command

grub-editenv manages GRUB's environment block (grubenv), which stores persistent variables across boots. The environment file is typically located at /boot/grub/grubenv or /boot/grub2/grubenv.
Common variables include saved_entry (the boot entry to use when GRUBDEFAULT=saved), **nextentry (entry for next boot only, used by grub-reboot), and recordfail** (set when a boot fails).
This tool enables scripted management of boot configuration without regenerating grub.cfg.

list

List all variables in the environment file

Set a variable to a value

Remove a variable

Create a new empty environment file

/boot/grub/grubenv

The GRUB environment block file storing persistent boot variables.

Must contain GRUB_DEFAULT=saved for grub-editenv settings to take effect.

The grubenv file has a fixed size (1024 bytes). Variables and values must fit within this space. Some bootloader configurations may not use grubenv. Changes require GRUB_DEFAULT=saved in /etc/default/grub.

grub-editenv is part of GRUB 2's saved default mechanism, allowing boot preferences to persist without modifying the main configuration file. This enables features like "boot once" and remembering the last successful boot.

grub-set-default(8), grub-reboot(8), grub-mkconfig(8)