[ Warning: I'm new to Python. Don't know it at all really yet, but had to examine some 3rd party code because of performance problems with it. ]
Here's a code snippet: i = 0 while (i < 20): i = i + 1 (shellIn, shellOut) = os.popen4("/bin/sh -c ':'") # for testing, the spawned shell does nothing print 'next' # for line in shellOut: # print line On my system (AIX 5.1 if it matters, with Python 2.4.3), this simple loop spawning 20 subshells takes .75 sec. Ok, that's reasonable. Now, if I uncomment the two commented lines, which loop over the empty shellOut array, the progam now takes 11 secs. That slowdown seems very hard to believe. Why should it slow down so much? John. -- http://mail.python.org/mailman/listinfo/python-list