If two GUIs are opened, however, only axes in a single GUI can be updated at one time, with axes in the other GUI "holding" until the other GUI stops trying to continuously plot.
As a simple test of this issue, I've created a GUI consisting of a single axes tagged 'plot Axes' and a togglebutton.
When the togglebutton is "depressed", random data is continuously plotted in the axes using the code: With the 'gui_Singleton' parameter set to 0, I opened two instances of this GUI.
Regarding "usually just run one instance of it" - we run several dozen instances of it to monitor remote servers.
It is only recommended for debugging and a limited number of sensors for a limited time.
PRTG Network Monitor front end is a web application.
The shell process knows nothing about the variables on the new process, explaining why We note the file system is handling concurrency issues, and in the circumstances the OP is not concerned about race conditions and other concurrency issues.
If only one copy of the script could run at a time, then the filename could be a constant.