/sys$common/syshlp/helplib.hlb MERGE, /DUPLICATES, Example  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  $ SORT/KEY=(POSITION:3,SIZE:5,DECIMAL)/NODUPLICATES -
  _$ ACCT1,ACCT2 ACCT.LIS

      This SORT command arranges the two input files according to
      the key supplied and eliminates all but one of multiple records
      with equal keys.