telnetlib

#! /usr/bin/env python

import telnetlib
import time
import socket
import sys

TELNET_PORT = 23
TELNET_TIMEOUT = 6

def send_command(remote_conn, cmd):
	cmd = cmd.rstrip()
	remote_conn.write("terminal length 0" + "\n")
	time.sleep(1)
	return remote_conn.read_very_eager()

def login(remote_conn, username, password):
	output = remote_conn.read_until("sername:", TELNET_TIMEOUT)
	remote_conn.write(username + '\n')
	output += remote_conn.read_until("assword:", TELNET_TIMEOUT)
	remote_conn.write(password  + '\n')
	return output

def telnet_connect(ip_addr):
	try:	
		return telnetlib.Telnet(ip_addr, TELNET_PORT, TELNET_TIMEOUT)
	except socket.timeout:
		sys.exit("Connection timed-out")

def main():
	ip_addr = "10.5.6.7"
	username = 'myuser'
	password = 'mypwd'

	remote_conn = telnet_connect(ip_addr)

	ouptut = login(remote_conn, username, password)
	time.sleep(1)
	output = remote_conn.read_very_eager()

	# Disable paging
	output = send_command(remote_conn, "terminal length 0")

	# Show version
	output = send_command(remote_conn, "show version")	

	remote_conn.close() 

# this runs the function if executed directly, instead of by importing from another script
if __name__ == "__main__":
	main()