On X11 systems, you can filter out the dpi number with the xdpyinfo command. On my system I get: 
screen #0:
  dimensions:    1280x1024 pixels (361x292 millimeters)
  resolution:    90x89 dots per inch

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If you have Tk available on your system, you can get the dpi number by using the screenheight, screenmmheight, screenwidth and screenmmwidth methods. See also the Tk::Widget documentation.

In reply to Re: Re: Conversion Modules from Pixels to Millimeters by eserte
in thread Conversion Modules from Pixels to Millimeters by Anonymous Monk

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