Boiled it down to octave. Solution is here:
http://stackoverflow.com/questions/22506624/how-to-make-octave-use-
gnuplot-instead-of-fltk-by-default
Use the command:
graphics_toolkit (gnuplot)
at the beginning of your octave scripts or in your private .octaverc file
e.g.
user@mycomputer:~$
Public bug reported:
GNU Octave, version 3.8.1, Ubuntu 14.04
gnuplot (Version 4.6 patchlevel 4, last modified 2013-10-02, Build System:
Linux x86_64)
OS: Ubuntu 14.04.1 LTS, Release:14.04
package:
octave: Installed: 3.8.1-1ubuntu1
gnuplot: Installed: 4.6.4-2
sample output:
octave:1
