Online resources that might be helpful:

• Grace related
  
  • Grace website
    http://plasma-gate.weizmann.ac.il/Grace/

• Gnuplot related
  
  • Gnuplot website
    http://www.gnuplot.info/
  • Einführung in gnuplot - Rechenzentrum Uni Osnabrück
    http://www.rz.uni-osnabrueck.de/Zum_Nachlesen/Skripte_Tutorials/Gnuplot_Einfuehrung/pdf/gnuplot.pdf
  • Gnuplot reference card
    http://www.gnuplot.info/docs_4.0/gpcard.pdf
  • Not so frequently asked questions about gnuplot
    http://t16web.lanl.gov/Kawano/gnuplot/index-e.html
• Gri related
  
  • Gri website
    http://gri.sourceforge.net
  • Gri reference card
    http://gri.sourceforge.net/refcard.pdf
  • Gri command reference card
    http://gri.sourceforge.net/cmdrefcard.pdf
  • Gri documentation
    http://gri.sourceforge.net/gri.pdf
• unrelated
  http://www.google.com ;)

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Good luck and may this tutorial help you for accomplishing further tasks!