ubuntu@ubuntu:~$ sudo cryptsetup luksOpen /dev/mapper/lvm-root luks
Enter passphrase for /dev/mapper/lvm-root:
ubuntu@ubuntu:~$ sudo mount /dev/mapper/luks /mnt
ubuntu@ubuntu:~$ sudo mount -o bind /dev /mnt/dev
ubuntu@ubuntu:~$ sudo mount -o bind /sys /mnt/sys
ubuntu@ubuntu:~$ sudo mount -t proc /proc /mnt/proc
ubuntu@ubuntu:~$ sudo cp /proc/mounts /mnt/etc/mtab
ubuntu@ubuntu:~$ sudo mount /dev/sda5 /mnt/boot
ubuntu@ubuntu:~$ sudo chroot /mnt /bin/bash
root@ubuntu:/#