How to conifgure to show plot online?

[sakurazerg007]

How to conifgure 'octave_kernel_config.py'? I hava th following error in octave 7:

plot(2,3)

Inline plot failed, consider trying another graphics toolkit
error: print: rendering with fltk toolkit requires visible figure (DISPLAY='')
error: called from
    _make_figures>safe_print at line 125 column 7
    _make_figures at line 49 column 13

[andresroliveira]

I do the following

$ echo "c.OctaveKernel.plot_settings = dict(backend='qt')" > ~/.jupyter/octave_kernel_config.py

or

$ echo "c.OctaveKernel.plot_settings = dict(backend='gnuplot')" > ~/.jupyter/octave_kernel_config.py

But in both cases the plot opens in a different window and I have the error

error: graphics_toolkit: qt toolkit is not available
error: called from
    graphics_toolkit at line 84 column 5

or the warning

warning: using the gnuplot graphics toolkit is discouraged

The gnuplot graphics toolkit is not actively maintained and has a number
of limitations that are unlikely to be fixed.  Communication with gnuplot
uses a one-directional pipe and limited information is passed back to the
Octave interpreter so most changes made interactively in the plot window
will not be reflected in the graphics properties managed by Octave.  For
example, if the plot window is closed with a mouse click, Octave will not
be notified and will not update its internal list of open figure windows.
The qt toolkit is recommended instead.