On Windows, Python 3.3.2, when I run Python as a subprocess via Popen("py -i somescript.py", stdin=PIPE, stdout=PIPE, stderr=PIPE).communicate() and somescript.py ends with exception, there is first interactive promt ">>>" in stderr output and then the traceback which is reversed to standard order when somescript.py is run interactively directly.

Corresponding StackOverflow question: http://stackoverflow.com/questions/18419724/position-of-prompt-in-stderr-after-systemexit .