plot3line2 — output a 2D UnixPlot line
plot3line2 outputs a UnixPlot command to draw a line in the XY plane from the point (x1 y1) to the point (x2 y2). These points can be floating point and the output is always written as a floating point plotting command. If you need an integer command then feed the output of this through plot3-plot3(1). If an optional [r g b] is given, where r, g, and b are values from 0 to 255 representing Red, Green, and Blue color values, the line will be drawn in that color. Otherwise the current drawing color (white by default) is used.
To allow this command to be used in pipelines, an optional input file can be given. All of the input will be passed through until end of file, and then the line will be appended to the end.
This command exists mostly as an aid for making graphs and things from shell commands.