's solution is much better than using notepad if these are supposed to be read-only files. With notepad the user can very easily accidently (or purposefully) delete/edit stuff and then save.
Second comment (assuming you still want to kick off a notepad) is that the above contains good info, especially on the Tk code. But to summarize what the tk code should run (e.g. system vs exec vs fork) I wanted to toss this list into the mix. It's from a recent