The command-line version of VGK (covered in Transonic Aerodynamics, Section 6b) has been superseded, in part, by the ESDU VGK Toolbox. Unless you have a specific requirement for the command line version you are recommended to use the ESDU VGK Toolbox.

ESDU 99032

VGK method for two-dimensional aerofoil sections (command line version). Part 5: design to a specified upper-surface pressure distribution.