grub: probe

 
 16.3.58 probe
 -------------
 
  -- Command: probe [--set var]
           --driver|--partmap|--fs|--fs-uuid|--label|--part-uuid device
      Retrieve device information.  If option '--set' is given, assign
      result to variable VAR, otherwise print information on the screen.
 
      The option '--part-uuid' is currently only implemented for MSDOS
      and GPT formatted disks.