A unique instance of Python GUI program

[akineko]

Hello everyone,

This may not be a Python specific challenge.
I have a GUI program written in Python + Tkinter.
It works very well.

Now, I would like to start it from a shell script.
As my GUI program includes a server, it should not have more than one
instance.
Is there any easy way to check if another instance of the program is
already running.

I vaguely remember that Windows programming provides a way to check.

A platform independent approach would be nice but a solution for X is
sufficient for my application.

Any comments will be greatly appreciated.

Best regards,
Aki Niimura