- Some configurations for the Kernel can only be made at
boot time.
- The bootloader is what passes the options to the Kernel when it is booted.
- GRUB2 is just called
GRUB nowadays, in case people talk generally about GRUB.
- GRUB1 had a config file
grub.conf and you edited that to add, remove or modify Kernel boot choices.
- For GRUB2 however:
/etc/default/grub
- Useful documentation to read, that is referenced in the file: `info -f grub -n ‘Simple configuration’
- There is also
/etc/grub.d
- You would usually edit
40_custom
- Files in this directory can start with a number.
- GRUB goes through each of these files in order, to provide a menu of choices on what you can boot.
- You can affect the order that items are listed, by placing a number in front of the file.
- You can have multiple Kernels to boot from or boot the same Kernel with different options.
- If you make changes, you generate the config file with:
grub2-mkconfig
- GRUB Interactivity:
- Can interrupt GRUB.
- When editing in GRUB Interactive, you are not changing the file on the disk, just temporarily editing the GRUB configuration.
- Can continue to boot with the changes with
'b' or Ctrl-x