# WARNING: destroys existing data
cryptsetup luksFormat /dev/sda5
cryptsetup luksOpen /dev/sda5 sda5_crypt
mkfs.ext4 /dev/mapper/sda5_crypt
cryptsetup luksOpen /dev/sda5 sda5_crypt
mount /dev/mapper/sda5_crypt /mnt/tmp
umount /mnt/tmp
cryptsetup luksClose sda5_crypt
dmsetup ls
(will list other logical volumes too)