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Systems & Data Center · Intermediate

GRUB 2

The GRand Unified Bootloader version 2, the standard Linux boot loader that loads the kernel and initramfs.

Definition

GRUB 2 configuration is generated from /etc/default/grub and scripts in /etc/grub.d by grub2-mkconfig (or update-grub on Debian). Kernel parameters can be edited at the boot menu for recovery, such as booting into rescue mode.

Example

Adding rd.break or systemd.unit=rescue.target to the kernel line at the GRUB menu enables root password recovery.

Exam tip

Never edit grub.cfg directly; change /etc/default/grub and regenerate it.

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