Rsync Backup

# rsync options source destination

# rsync -r -t -p -a -v --progress --delete -u -s source destination

Grub Restore

sudo mount /dev/sdb1 /mnt

sudo mount --bind /dev /mnt/dev &&
sudo mount --bind /dev/pts /mnt/dev/pts &&
sudo mount --bind /proc /mnt/proc &&
sudo mount --bind /sys /mnt/sys

sudo chroot /mnt

grub-install /dev/sda

grub-install --recheck /dev/sda

update-grub

exit &&
sudo umount /mnt/sys &&
sudo umount /mnt/proc &&
sudo umount /mnt/dev/pts