=> ncdump -h main_hdf_file.hdf5                                               
   netcdf main_hdf_file {                                                          
   dimensions:                                                                     
           time = 5 ;                                                              
   variables:                                                                      
           double corrected_sea_level(time) ;                                      
                   string corrected_sea_level:name = "corr sea level" ;            
                   corrected_sea_level:scale_factor = 1. ;                         
                   corrected_sea_level:_FillValue = -9999 ;                        
                   string corrected_sea_level:units = "mm" ;                       
           double sea_level(time) ;                                                
                   string sea_level:name = "sea level" ;                           
                   sea_level:scale_factor = 1. ;                                   
                   sea_level:_FillValue = -9999 ;                                  
                   string sea_level:units = "mm" ;                                 
           double time(time) ;                                                     
                   string time:name = "time" ;                                     
                   string time:units = "seconds since 19700101T00:00:00" ;         
                                                                                   
   // global attributes:                                                           
                   string :Conventions = "CF-1.0" ;                                
                   string :history = "the hdf file has been created by EGADS" ;    
                   string :comments = "no comments on the hdf file" ;              
                   string :institution = "My institution" ;                        
   }                                                                               