Python not able to get iotop output

Question

I am working on a python script which needs to read the output of iotop. But stdout appears to be blank. The goal is to have the output of iotop stored as a string which I can then later search and use. This is running on Ubuntu 16.04 w/ python 3.6. I am calling the script with "sudo python3.6 script.py" as iotop requires admin rights.

p = subprocess.Popen(['iotop','-b','-n','1','-a','-k'], stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True)
try:
    outs, errs = p.communicate(timeout=15)
except subprocess.TimeoutExpired:
    p.kill()
    outs, errs = p.communicate()
returncode=p.returncode
print(outs.decode('UTF-8'))

Running this command in the bash terminal gives me the expected output. What am I doing wrong?

sudo iotop -b -n 1 -a -k

Answer 1

"-n"和"1"应该是单独的列表元素

Answer 2

删除shell=True使代码按照我想要的方式工作。

p = subprocess.Popen(['iotop','-b','-n','1','-a','-k'], stdout=subprocess.PIPE, stderr=subprocess.PIPE)