Part 3 of my series on scientific computing underdogs!!!
gnuplot has been around for a long, long time. One of its main features is that it can run as a session, in a terminal. This is helpful when graphics are not available, e.g. in a remote login session. Just type “set terminal dumb” to get a gorgeous, ascii plot of your data. The session uses a language that is also largely common to awk, which is nice. E.g.
plot ‘file.dat’ using ($3*1000):(log($2))
plots log of column 2 of the datafile versus column 3, multiplied by 1000.
Another nice feature is its 3D capabilities, including 2D level maps of 3D functions.