ubuntu@ubuntu:/$ sudo mount /dev/sda7 /mnt
ubuntu@ubuntu:/$ sudo mount --bind /dev /mnt/dev
ubuntu@ubuntu:/$ sudo mount --bind /dev/pts /mnt/dev/pts
ubuntu@ubuntu:/$ sudo mount --bind /proc /mnt/proc
ubuntu@ubuntu:/$ sudo mount --bind /sys /mnt/sys
ubuntu@ubuntu:/$ sudo chroot /mnt
root@ubuntu:/# grub-install /dev/sda
grub-install: errore: /usr/lib/grub/i386-pc/modinfo.sh doesn't exist. Please specify --target or --directory.
root@ubuntu:/#