run command and get output python subprocess code example

Example 1: python run command and read output

#!/usr/bin/python
import subprocess, sys
## command to run - tcp only ##
cmd = "/usr/sbin/netstat -p tcp -f inet"
## run it ##
p = subprocess.Popen(cmd, shell=True, stderr=subprocess.PIPE)
## But do not wait till netstat finish, start displaying output immediately ##
while True:
    out = p.stderr.read(1)
    if out == '' and p.poll() != None:
        break
    if out != '':
        sys.stdout.write(out)
        sys.stdout.flush()

Example 2: python get output

>out = subprocess.Popen(['wc', '-l', 'my_text_file.txt'], 
           stdout=subprocess.PIPE, 
           stderr=subprocess.STDOUT)