The Plot Twists » Linux Magazine : vimarsana.com

Use Gnuplot with command-line utilities.
Some excellent charting and plotting packages can be found, but if you re like me, you sometimes just want to do a quick dynamic test plot without a lot of custom setup. Gnuplot is a command-line charting utility that has been around for a while, and I was amazed how easy it was to get up and running. In only 20 lines of scripting code, I was able to create real-time line and bar charts.
In this article, I introduce Gnuplot with two dynamic examples: The first shows the status of Raspberry Pi I/O pins, and the second is a line chart of CPU diagnostics.