how to write and read from a sub process continously in python code example
Example: python subprocess print stdout while process running
from subprocess import Popen, PIPE, CalledProcessError
with Popen(cmd, stdout=PIPE, bufsize=1, universal_newlines=True) as p:
for b in p.stdout:
print(b, end='') # b is the byte from stdout
if p.returncode != 0:
raise CalledProcessError(p.returncode, p.args)