the HDF command line utilities are application programs that can be executed by entering them at the command level, just like UNIX commands.

There are HDF utilities to: 

They provide capabilities for doing things with HDF files for which you would normally have to write your own program.

The hdp utility is one of the more useful HDF utilities. Following is a description of its function:

It provides quick information about the contents and data objects in an HDF file. It can list the contents of hdf files at various levels with different details. It can also dump the data of one or more objects in the file in binary or ASCII format.

The other utilities are: 

In addition, the netCDF utilities, ncdump and ncgen, COMPILED with the HDF library, are included.