GNU GRUB is a Multiboot boot loader. Briefly, a boot loader is the first software program that runs when a computer starts. It is responsible for loading and transferring control to the operating system kernel software (such as the Hurd or Linux). The kernel, in turn, initializes the rest of the operating systemThe Grub Boot Loader Manual provides beginners with a simple introduction to the basics, and experts will find advanced details they need.In this you will see the following things below.1 Introduction to GRUB2 Naming convention3 OS-specific notes about grub tools4 Installation5 Booting6 Writing your own configuration file7 Theme file format8 Booting GRUB from the network9 Using GRUB via a serial line10 Using GRUB with vendor power-on keys11 GRUB image files12 Core image size limitation13 Filesystem syntax and semantics14 GRUB’s user interface15 GRUB environment variables16 The list of available commands17 Internationalisation18 Security19 Platform limitations20 Outline21 Supported boot targets22 Error messages produced by GRUB23 Invoking grub-install24 Invoking grub-mkconfig25 Invoking grub-mkpasswd-pbkdf226 Invoking grub-mkrelpath27 Invoking grub-mkrescue28 Invoking grub-mount29 Invoking grub-probe30 Invoking grub-script-checkYou will find all this section offline without any internet connection and learn Grub easily anywhere and anytime.