how do I pipe two processes?

[Bilgehan.Balban at gmail.com]

Hi, I want to pipe output of process A to B, and read output of B from
python. On Unix if I do the following:

child_out, child_in = popen2("program_a | program_b")

line = child_out.readline()

I get "IOError: bad file descriptor" from Python, and broken pipe
error from program_b. How do I do this right?

Thanks,
Bahadir