Reading/writing to a Popen() subprocess

Question

I\'m trying to talk to a child process using the python subprocess.Popen() call. In my real code, I\'m implementing a type of IPC, so I want to write some data, read the respons

Answer 1

I would try to use Popen().communicate() if you can as it does a lot of nice things for you, but if you need to use Popen() exactly as you described, you'll need to set sed to flush its buffer after newlines with the -l option:

p = subprocess.Popen(['sed', '-l', 's/a/x/g'],
                     stdout=subprocess.PIPE,
                     stdin=subprocess.PIPE)

and your code should work fine