You replaced the boot disk in a BIOS/MBR system and need to write the GRUB 2 boot loader into the master boot record of /dev/sda, installing the required GRUB modules under /boot. Which command does that?
LPIC-1 Exam 101-500, objective 102. Linux installation and package management medium
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The options
Not correct grub-mkconfig -o /boot/grub/grub.cfg
Wrong. This only regenerates the menu configuration file. It writes nothing to the disk's boot sector, so a disk with no boot loader stays unbootable.
Correct grub-install /dev/sda
Correct. grub-install writes the boot image to the target device's boot sector and copies the GRUB modules and core image into /boot/grub.
Not correct grub-mkrescue -o /dev/sda
Wrong. grub-mkrescue builds a bootable rescue ISO image; -o names an image file to create, not the system disk to install onto.
Not correct update-grub /dev/sda
Wrong. update-grub is a Debian/Ubuntu wrapper that just runs 'grub-mkconfig -o /boot/grub/grub.cfg' to rewrite the menu file. It writes no boot loader to any device, and a device argument is not valid for it.
Why
Keep the two GRUB 2 halves apart. grub-install puts the boot loader itself onto a device (MBR or the EFI system partition). grub-mkconfig, and its Debian wrapper update-grub, only rebuild the menu file grub.cfg. Installing a new disk needs the first; adding a kernel needs the second.
Where this comes from
- Cited
- LPI exam objective 102.2
- What it says
- Install and configure a boot loader such as GRUB 2, including interacting with the boot loader.
Practise this
Reading one question is not practice. The trainer will draw a set from objective 102 and space the ones you get wrong.