ubuntu-gnome@ubuntu-gnome:~$ sudo mount /dev/sda1 /mnt
mount: /dev/sda1 is already mounted or /mnt busy
       /dev/sda1 is already mounted on /mnt
ubuntu-gnome@ubuntu-gnome:~$ sudo mount --bind /proc /mnt/proc
mount: mount point /mnt/proc does not exist
ubuntu-gnome@ubuntu-gnome:~$ sudo mount --bind /sys /mnt/sys
mount: mount point /mnt/sys does not exist
ubuntu-gnome@ubuntu-gnome:~$ sudo chroot /mnt
chroot: failed to run command ‘/bin/bash’: No such file or directory
ubuntu-gnome@ubuntu-gnome:~$