Ubuntu 14.04修复grub

1.进livecd

2.sudo fdisk -l 找到安装分区

3.sudo mount /dev/sda? /mnt 挂载安装分区

4.sudo mount --bind /dev /mnt/dev

   sudo mount --bind /proc /mnt/proc

   sudo mount --bind /sys /mnt/sys

5.sudo chroot /mnt

6.grub-install /dev/sda

7.grub-mkconfig -o /boot/grub/grub.cfg