I am upstreaming this for two reasons:
1. Traditionally I have done this by hand in a spreadsheet program. I would
rather just have a program fix it up for me.
2. Multiple people have asked me about how to produce this sort of graph and I
would just like to document it via a script.
I hope it is useful to others. You use the script by invoking it as:
./csvcolumn_to_scurve <input_file> <before_column> <after_column> [output_file]
