Executing script using subprocess.Popen twice interactively fails
without error the second time. File a.py:

print "start"
import subprocess

print "first call"
process = subprocess.Popen(
	args   = "cmd.exe /c echo 1",
	stdout = subprocess.PIPE)

for line in process.stdout:
	if not line:
		break;
	print line;

print "second call"
process = subprocess.Popen(
	args   = "cmd.exe /c echo 2",
	stdout = subprocess.PIPE)

for line in process.stdout:
	if not line:
		break;
	print line;

print "end"

Executing it in Python on Windows, interactively:

Python 2.5.1 (r251:54863, Apr 18 2007, 08:51:08) [MSC v.1310 32 bit
(Intel)] on
win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import a
start
first call
1

second call
2

end
>>> import a
>>>

Top-level statements are executed only the first time the module is
imported:
http://docs.python.org/tut/node8.html#moreModules
To execute a script from python, you should consider the execfile()
function instead.

Bah, silly me, I apologize, and thank you for the quick feedback.