DO is a customizeable utility to analyse and identify associations in a database
of astronomical observations. The following commands are available:
CREATE/OST    create an Observation Summary Table (OST) from a set of 
              FITS files or MIDAS images (.bdf) 
CREATE/CRULE  create classification rules for an OST 
CLASSIFY/IMA  apply a given rule to a OST 
ASSOCIATE/IMA associate suitable calibrations frames to a scientific 
              exposure 
GROUP/ROW     group the rows of a table by the value of one of its 
              column