Gnu plot is an amazing tool. It's great for generating quick plots from bash. I've had my programs generate statistical data and then thrown it into gnuplot so I can better understand how my program is behaving. Unfortunately every time I use it I end up having to go back to the web to relearn the basic syntax of creating a line graph. I'm going to try and save myself some time by documenting the basic usage here.
To draw a simple line graph first place the points to draw in a separate file in this case named "gnuplot.data"
Now create the gnuplot script:
The pause line at the end keeps the gnuplot from flashing the graph and then immediately exiting. When you execute gnuplot you'll see the following:
There is a ton more you can do with gnuplot like generate png files, create different types of graphs, but I've found that as a simple programming tool this gets me 90% there. For more information checkout the gnuplot homepage. Happy plotting