inferior-octave-startup-file

inferior-octave-startup-file is a variable defined in `octave.el'.
Its value is

"~/.emacs.d/init_octave.m"

Documentation:
Name of the inferior Octave startup file.
The contents of this file are sent to the inferior Octave process on
startup.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 24.4 of Emacs.