+1 for gnuplot. Amazingly powerful and flexible, and exports to png, pdf, eps, latex, etc. Possibly outdated in some aspects but still unbeatable AFAIK.

That being said, this sounds nice for adding interactivity (sliders to vary parameters, that sort of stuff). Useful in presentations and the sort.

I severely dislike Gnuplot, but then again, I am wedded to Python. I'm not sure how versatile it is, at least from the slightly acquainted position I am.

FYI it's really dead simple to write new "bokeh" command line tools as Bokeh apps now. We already have several ("bokeh html" and "bokeh json") but we are definitely interested in make a gnuplot-like bokeh command line tool that you can just point at a CSV or log file and get a visualization right out. E.g. something like "bokeh graph foo.log -x time -y connections --tail" would create an automatically updating visualization of a growing log file. Or if anyone is interested in this functionality and wants to help speed along the development, please let us know!