How can I tell which format a netCDF file uses?
The short answer is that under most circumstances, you should not care, if you use version 4.0 or later of the netCDF library to access data in the file. But the difference is indicated in the first four bytes of the file, which are ‘C’, ‘D’, ‘F’, ‘\001’ for the classic netCDF format; ‘C’, ‘D’, ‘F’, ‘\002’ for the 64-bit offset format; or ‘\211’, ‘H’, ‘D’, ‘F’ for an HDF5 file, which could be either a netCDF-4 file or a netCDF-4 classic model file. (HDF5 files may also begin with a user-block of 512, 1024, 2048, …
