root@ubuntu:~# grub-install
install_device not specified.
Usage: grub-install [OPTION] install_device
Install GRUB on your drive.
-h, --help print this message and exit
-v, --version print the version information and exit
--root-directory=DIR install GRUB images under the directory DIR
instead of the root directory
--grub-shell=FILE use FILE as the grub shell
--no-floppy do not probe any floppy drive
--force-lba force GRUB to use LBA mode even for a buggy
BIOS
--recheck probe a device map even if it already exists
INSTALL_DEVICE can be a GRUB device name or a system device filename.
grub-install copies GRUB images into the DIR/boot directory specfied by
--root-directory, and uses the grub shell to install grub into the boot
sector.
Report bugs to <bug-grub@gnu.org>.
root@ubuntu:~# update-grub
Searching for GRUB installation directory ...
No GRUB directory found.
To create a template run 'mkdir /boot/grub' first.
To install grub, install it manually or try the 'grub-install' command.
### Warning, grub-install is used to change your MBR. ###