[Tkinter] Defining a self made module's function to interact with the main .py variables?

[Gribouillis]

You can add a file handle argument to clr_yes_fn_no_print_output()

def clr_fn_no_print_output(host, file=sys.stdout):
    ...
    for line in p.stdout:
        print(line, end=' ', file=file)

Then in the code that calls this function you give a StringIO instance as file argument

import io

ofh = io.StringIO()
clr_fn_no_print_output(host, file=ofh)
self.text_window.insert(tk.END, ofh.getvalue())

It's an example of dependency injection. As far as I know, functions that do input output operations are good candidates for dependency injection.

The drawback of this code is that the GUI will freeze during the call to clr_fn_no_print_outut(). To avoid this, you can use the technique with the after() method as I said in your other thread about this subject.