How to tell if invoked through IDLE or command line?

[Michael Hoffman]

Robert D. Young wrote:
> I've probably asked this before, but how can I tell within the program I'm
> running if the .py files was involved by "run module" in IDLE or by using
> the .py assoication with the python.exe program? I'd like to prevent running
> under certain circumstances, or pop-up warnings, or change character
> displays (some look different when run under IDLE).

sys.modules.keys() contains "idlelib" is a simple way of doing it, 
assuming you never import idlelib otherwise (and why would you?)
-- 
Michael Hoffman