Getting progress message from a subprocess

Question

I want to start a program which needs several minutes to complete. During this time I want to read the progress message of the program (which are printed on the stdout). The pro

Answer 1

You can do a poll on the status of your subprocess and keep outputting lines.

p = subprocess.Popen('ls;sleep 10', shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)

rc = p.poll()
while rc != 0:
    while True:
        line = p.stdout.readline()
        if not line:
            break
        print line
    rc = p.poll()

assert rc == 0