Change filepath of the .blend without saving

I have a script that load a file and imports objects to it to quickly set up a scene I can manually edit and save then, but the problem is that if I save it it is going to overwrite the set up file I have loaded object into. Can I change ( read-only) or somehow mark file as unsaved. Also script is run from command line, is there maybe an argument that does this.

Couldn’t you let the script run a save-as operation?

Yes, but I don’t use --background option I wanted to open the file and let the user modify the file before saving and when he presses save to be asked about location where to save or file is deleted if he quits.
To be specific I’m making a tool to transfer objects from Unity to Blender and set up materials so I can quickly bake them or texture pack them…

You should be able to either call the save as operator, or even duplicate the file with OS functions by a script. I don’t think you can force the user to save as if the blend was unsaved before.

Thanks. I was hopping there is some function that Blender uses for it’s startup file that can be used to load custom startup file for single run. But save as at some default path looks simpler than replacing and reverting the startup file on launch.