Tends to be Ciro Santilli's first attempt for quick and dirty graphing: github.com/cirosantilli/gnuplot-cheat.
When it doesn't, you Google for an hours, and then you give up in frustration, and fall back to Matplotlib.
Couldn't handle exploration of large datasets though: Survey of open source interactive plotting software with a 10 million point scatter plot benchmark by Ciro Santilli
New to topics? Read the docs here!