Error in print latex standalone

[Joao Rodrigues]

Hi

I want to generate standalone plots with superscripts/Latex annotations in the text, but I am getting error messages.

An example from the manual (https://octave.org/doc/v4.4.0/Printing-and-Saving-Plots.html):

x = 0:0.01:3;
hf = figure ();
plot (x, erf (x));
hold on;
plot (x, x, "r");
axis ([0, 3, 0, 1]);
text (0.65, 0.6175, ['$\displaystyle\leftarrow x = {2 \over \sqrt{\pi}}'...
                     '\int_{0}^{x} e^{-t^2} dt = 0.6175$'],
      "interpreter", "latex");
xlabel ("x");
ylabel ("erf (x)");
title ("erf (x) with text annotation");
print (hf, "plot15_7.pdf", "-dpdflatexstandalone");

yields:

error: print.m: error opening file 'plot15_7.tex'
error: called from
    print>latex_standalone at line 686 column 5
    __opengl_print__ at line 176 column 5
    print at line 434 column 14

The version is GNU Octave, version 4.0.0 and the operating system is Ubuntu 16.04.5 LTS.

Any suggestion is appreciated.