GrubInstall

Grubinstall is a commonly used name for the GRUB bootloader installation utility, typically invoked as grub-install. It is part of the GRUB 2 project and is responsible for installing or updating the bootloader on a computer’s disk or EFI system partition. The tool works in conjunction with other GRUB components to ensure that the system can boot into the configured operating system(s).

Grubinstall operates in two main modes depending on the system’s firmware: legacy BIOS with MBR installations and UEFI with an EFI System Partition. For BIOS systems, it writes a boot sector to the target device (such as /dev/sda) and installs the GRUB stage files into the /boot/grub directory. For UEFI systems, it copies and registers the GRUB EFI binary within the EFI System Partition and creates or updates a boot entry. The exact behavior is controlled by a set of options that specify the target architecture, the device, and the location of the EFI directory if applicable.

Typical usage involves specifying a target and, in many cases, the installation destination. Examples include grub-install --target=i386-pc /dev/sda for a legacy BIOS setup, or grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=GRUB /dev/sda for UEFI. After installation, it is common to generate or update the boot menu by running a separate configuration command such as grub-mkconfig -o /boot/grub/grub.cfg.

Notes and caveats: grub-install must be run with root privileges and is sensitive to the system’s mounted partitions and chroot status when repairing a installed system from a live environment. On UEFI systems, the EFI System Partition must be mounted, and the correct --bootloader-id and --efi-directory parameters used.

See also: GRUB, grub-mkconfig, grub-update, boot management.