>How would you use scan command to look for repeated records in a table ?

If you take care of array limit you can do something like:

FUNCTION FindDupes(tcAlias)
CREATE CURSOR DupRecs (rec1 i, rec2 i)

SELECT (m.tcAlias)
DIMENSION oRecords[RECCOUNT()]
SCAN
  SCATTER NAME oRecords[RECNO()] memo
ENDSCAN

SCAN
  SCATTER NAME oCurrent memo
  FOR ix = RECNO() + 1 TO ALEN(oRecords)
    IF COMPOBJ( oCurrent, oRecords[m.ix] )
      INSERT INTO DupRecs (rec1,rec2) VALUES (RECNO(m.tcAlias),m.ix)
      INSERT INTO DupRecs (rec1,rec2) VALUES (m.ix,RECNO(m.tcAlias))
    endif
  ENDFOR
ENDSCAN

Cetin