Catch22?

[Leland Smith]

I have modified a Matlab program so it runs in Octave.  I would like to write ascii output data files, which I can do with the limitation that I need to use a script embedded file name.  I want to input any filename I choose to my script, but to that I need to make my script a function, and using a function I can't access my data since it isn't declared global in the Matlab script.
Has anyone one across this issue?