Update 2015-03-15: As Antiplex mentioned in the comments, the resources are slighlty out of date. An update is pending I use my laptop (Lenovo Z370, with Ubuntu 11.10) a lot in the college. Unfortunatly there aren’t enough plugs in the wall for all students and I’m not willing to bring a plug board with me every time. So my approach to the problem was to improve the energy consumption of my laptop.
On my pursuade for a tool to visualize simple list values I found gnuplot: from Wikipedia: gnuplot is a command-line program that can generate two- and three-dimensional plots of functions, data, and data fits. I will focus on the capabilities of gnuplot on two-dimensional plots and in special howto visualize data without a corresponding second data value. But first here is the idea why I needed such a tool: