gnuplot

A graph plotter that outputs in several formats. More information: http://www.gnuplot.info/.

Start the interactive graph plotting shell:

gnuplot

Plot the graph for the specified graph definition file:

gnuplot {{path/to/definition.plt}}

Set the output format by executing a command before loading the definition file:

gnuplot -e "{{set output "path/to/filename.png" size 1024,768}}" {{path/to/definition.plt}}

Persist the graph plot preview window after gnuplot exits:

gnuplot --persist {{path/to/definition.plt}}