This example create a new ``CERN population'' Ntuple with all the people of 50 years old counted twice.

Usage of  NTUPLE/MERGE
                                                                                    
      opt stat                                                                                                          
      hi/file 1 rwn_aptuple.hbook                                                                                       
1     HI/FILE 2 RWN_APTUPLE_MERGE.HBOOK ! N                                                                      
2     NTUPLE/DUPLICATE //LUN1/10 12 title='CERN Population +50'                                                  
      hrout 12                                                                                                          
3     NTUPLE/MERGE //LUN1/10 //LUN2/12                                                                           
      hrout 12                                                                                                          
3     NTUPLE/MERGE //LUN1/10 //LUN2/12 AGE=50                                                                    
      hrout 12                                                                                                          
      nt/plot //lun2/12.age                                                                                             

1. Create a new hbook file.
2. The command NTUPLE/DUPLICATE create an empty Ntuple (here 12) with the same structure as a reference one (here //lun1/10).
3. The command NTUPLE/MERGE allows to concatanate Ntuple. Note that some selection criteria can be apply on the first ntuple identifier. This command acts only one Row Wise Ntuples.