1 DIRECTORY
  Syntax: DIRECTORY [id1][:id2] [&idb][:idb2]

  Alias  for INDEX.
  Gives a directory of the histograms currently in  memory. If you specify
  the primary identifier,  you will  get an  index of  all histograms with
  that identifier.  To get all  the histograms with a particular secondary
  identifier, give the  command   `DIRECTORY 0  &idb'.   To  get   all the
  histograms  in a particular  range,  give the command
  `DIRECTORY id1:id2 &idb1:idb2'.

