Stop a command line command in script

I'm writing a script in which I want to be able to run a command line command, probably with os.system("stuff"). But what if my command doesn't end on its own? Like, normally in my terminal I have to ctl+C to end it. Is there a way that I can run it, stop it, and grab the output?

I'm sure there has to be but I don't know it, and I'm not sure if I know the correct terminology to find it (all my Python is self-taught from experimenting)

Thanks!