When you are exploring a problem, in general first write a command-line program whenever possible.
It will take less effort to write then a full-blown GUI.
Recently I wrote a program to remove the protection from ms-excel files.
The original version was written as a command-line program. Later I re-used the relevant code for a GUI program for use on ms-windows. This was mainly for the benefit of some colleagues who are not comfortable with using the command-line.
In this article I want to contrast the two programs.