root@ubuntu:/home/ubuntu# sudo umount /mnt/* /mnt
umount: /mnt/bin: not mounted
umount: /mnt/boot: not mounted
umount: /mnt/cdrom: not mounted
umount: /mnt/dev: target is busy
(In some cases useful info about processes that
use the device is found by lsof(8) or fuser(1).)
umount: /mnt/etc: not mounted
umount: /mnt/home: not mounted
umount: /mnt/initrd.img: not mounted
umount: /mnt/initrd.img.old: not mounted
umount: /mnt/lib: not mounted
umount: /mnt/lib32: not mounted
umount: /mnt/lib64: not mounted
umount: /mnt/lost+found: not mounted
umount: /mnt/media: not mounted
umount: /mnt/mnt: not mounted
umount: /mnt/opt: not mounted
umount: /mnt/root: not mounted
umount: /mnt/sbin: not mounted
umount: /mnt/srv: not mounted
umount: /mnt/tmp: not mounted
umount: /mnt/usr: not mounted
umount: /mnt/var: not mounted
umount: /mnt/vmlinuz: not mounted
umount: /mnt/vmlinuz.old: not mounted
umount: /mnt/webmin-setup.out: not mounted
umount: /mnt: target is busy
(In some cases useful info about processes that
use the device is found by lsof(8) or fuser(1).)