LinuxQuestions.org - python2.x : automating ssh with subporcess call

Hi Friends,
I am new to python, kind of migrating from bash to python. here is thing I am trying to do with my pythong script.

ssh system and get some info from that system. I want it all automated. here is where I am strucked
script is pormpting me for ssh password

given below is my script
OS : fedora20
sshd daemon is running.

Code:

#!/usr/bin/python

from subprocess import Popen, PIPE

from sys import argv

script, ip = argv

username="test"

passwd="password"

command = "ssh -l %r %r 'echo hello >> /tmp/test.txt'" % (username,ip)



proc = Popen([command], stdin=PIPE,stdout=PIPE,stderr=PIPE,shell=True)



#proc.communicate(passwd)

proc.communicate("password\n")

How I execute script

Code:

$python ./python_ssh.py 192.168.1.20

test@192.168.1.20's password:

when I run above script it prompts me for password. Kindly suggest me where I am doing wrong, if any good e-book or link for learning subprocess is also welcome.

regards