Python PIPE to popen stdin

Question

I am attempting something very similar to real time subprocess.Popen via stdout and PIPE

I, however, want to send input to the running process as well.

If I

Answer 1

The select module in the standard library is made for these kind of situation:

process = subprocess.Popen(cmd,stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)

while True:
   reads,writes,excs = select.select([process.stdout, process.stderr], [process.stdin], [], 1)
   for r in reads:
       out = r.read(1)
       display.insert(INSERT, out)
       sys.stdout.write(out)
       sys.stdout.flush()
   for w in writes:
       w.write('a')

You can pass a list of file objects or file descriptors to select() which will return those files that are have data ready for read/write or until an optional timeout.

The select module works on both Windows and Unix-like systems (Linux, Macs, etc).