GRUB is configured using grub.cfg, usually located under /boot/grub. This file is quite flexible, but most users will not need to write the whole thing by hand.
|• Simple configuration:
|Recommended for most users
|• Root Identifcation Heuristics:
|Summary on how the root file system is identified.
|• Shell-like scripting:
|For power users and developers
|• Multi-boot manual config:
|For non-standard multi-OS scenarios
|• Embedded configuration:
|Embedding a configuration file into GRUB