The suffix HGL identifies files that contain data in the page description and plotter control language HP-GL (HPGL) in an ASCII text. Hewlett-Packard developed this language for the control of pen plotters, it was subsequently adopted by other manufacturers. Inkjet (inkjet) and laser printers can also be controlled with HP-GL.
HP-GL files are also used for the exchange of vector data. Many CAD programs support export in HP-GL format. However, they can also be generated by printing in a file and setting a corresponding printer / plotter eg The HP750C. However, this method also carries risks because full compatibility can not be guaranteed.
For these files the extensions hpgl, plt, hpg, pgl and more rarely prn are used. Changing the extension may be useful unless the file can be opened directly.