input string from find . -type f -iname "*.nc" | while read i; do ncdump -h "$i"; done | grep -E "long_name|units"

output is comma delimited param info: name, description, units

• [required] source of definition is netcdf long_name
• [optional] source of units is netcdf units

If redundant parameters you will want to do a sort and uniq after this.