* Replace all backticks with '$(...)'.
* Option to not output serial number => '--no-serial'
* Comment out part of the MD check - if 'sda3' was part of 'md11', then md="md113'
  which is just ... 'weird'!
  Untill I remember why I did that, it's commented out.
* Catch a ZFS VDEV that isn't raid, mirror, cache or spare.
* Get mount point (and filesystem)