Unclear:

Do you want the 'external program' to return data to the Tk GUI ap (which then mungs that data or consolidates the output of 'external program' to a single file)
-- or -- some other alternative not mentioned here?

... or are you iterating over the members of a set of records (construed very loosely) with one complete run of the 'external program' required per data point (perhaps, manually input or selected via the Tk GUI)?

If not, does the Tk GUI exist merely to protect users from the terrors of the command line interface?

You have several suggestions on how to do what you've asked about, but it would be easier to offer actual help if you provided details of the interaction (if any) between what the 'external program' does and what your Tk GUI tries to do.

In reply to Re: Launch External App in Tk And Return by ww
in thread Launch External App in Tk And Return by ~~David~~

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