//TOOLIN DD *
MERGE FROM(IN01,IN02,IN03,IN04,IN05) TO(OUTPUT) USING(MERG)
//MERGCNTL DD *
  OPTION EQUALS
  MERGE FIELDS=(21,4,CH,A)
/*

This example merges 5 input files to an output file. EQUALS is used to ensure that records that collate identically are output in the order specified in the FROM operand. For example, if IN01, IN03 and IN05 all have records with a key or 'AAAA' in positions 21-24, the output will contain the 'AAAA' record from IN01, the 'AAAA' record from IN03 and the 'AAAA' record from IN05, in that order.