Netgen command line approach

This works for version 4.9 but does not for 5.3.1 (only GUI mode).

$  netgen -batchmode  -geofile=cone.geo -meshfile=cone.ng -coarse

$  netgen -batchmode  -geofile=cone.geo -meshfile=cone.ngn  -meshfiletype="Neutral Format"

The possible mesh size options are
-verycoarse
-coarse
-moderate
-fine
-veryfine