text: usage: h5format_convert [OPTIONS] file_name
    OPTIONS
     -h, --help                Print a usage message and exit
     -V, --version             Print version number and exit
     -v, --verbose             Turn on verbose mode
     -d dname, --dname=dataset_name    Pathname for the dataset
     -n, --noop                Perform all the steps except the actual conversion
  
  Examples of use:
  
  h5format_convert -d /group/dataset file_name
    Convert the dataset </group/dataset> in the HDF5 file <file_name>:
      a. chunked dataset: convert the chunk indexing type to version 1 B-tree
      b. compact/contiguous dataset: downgrade the layout version to 3
      c. virtual dataset: no action
  
  h5format_convert file_name
    Convert all datasets in the HDF5 file <file_name>:
      a. chunked dataset: convert the chunk indexing type to version 1 B-tree
      b. compact/contiguous dataset: downgrade the layout version to 3
      c. virtual dataset: no action
  
  h5format_convert -n -d /group/dataset file_name
    Go through all the steps except the actual conversion when 
    converting the dataset </group/dataset> in the HDF5 file <file_name>.
  h5format_convert error: missing file name
  