How can i get telnet output printed line by line?

Question

I have implemented a script that connects to a Cisco device and collects the show run output.

The script is:

import getpass
import telnetlib
import time


HOST = "10.62.149.9"
user = input("Enter your remote account: ")
password = getpass.getpass("User Password: ")
enable = getpass.getpass("Enable Password: ")

tn = telnetlib.Telnet(HOST)

tn.read_until(b"Username: ")
tn.write(user.encode('ascii') + b"\n")
if password:
    tn.read_until(b"Password: ")
    tn.write(password.encode('ascii') + b"\n")
tn.write(b"enable\n")
if enable:
    tn.read_until(b"Password: ")
    tn.write(enable.encode('ascii') + b"\n")
tn.write(b"term len 0\n")
tn.write(b"show run\n")
time.sleep(10)
s = tn.read_very_eager()
print (s)
tn.close()

The script output is:

\r\ninterface GigabitEthernet1/0/26\r\n!\r\ninterface GigabitEthernet1/0/27\r\n!\r\ninterface GigabitEthernet1/0/28\r\n!\r\ninterface GigabitEthernet1/0/29\r\n!\r\ninterface GigabitEthernet1/0/30\r\n!\r\ninterface GigabitEthernet1/0/31\r\n!\r\ninterface GigabitEthernet1/0/32\r\n!\r\ninterface GigabitEthernet1/0/33\r\n!\r\ninterface GigabitEthernet1/0/34\r\n!\r\ninterface GigabitEthernet1/0/35\r\n!\r\ninterface GigabitEthernet1/0/36\r\n!\r\ninterface GigabitEthernet1/0/37\r\n!\r\ninterface GigabitEthernet1/0/38\r\n!\r\ninterface GigabitEthernet1/0/39\r\n!\r\ninterface GigabitEthernet1/0/40\r\n!\r\ninterface GigabitEthernet1/0/41\r\n!\r\ninterface GigabitEthernet1/0/42\r\n!\r\ninterface GigabitEthernet1/0/43\r\n!\r\ninterface GigabitEthernet1/0/44\r\n!\r\ninterface GigabitEthernet1/0/45\r\n!\r\ninterface GigabitEthernet1/0/46\r\n!\r\ninterface GigabitEthernet1/0/47\r\n!\r\ninterface GigabitEthernet1/0/48\r\n no switchport\r\n ip address 10.62.149.9
255.255.255.128\r\n!\r\ninterface GigabitEthernet1/0/49\r\n!\r\ninterface GigabitEthernet1/0/50\r\n!\r\ninterface GigabitEthernet1/0/51\r\n!\r\ninterface GigabitEthernet1/0/52\r\n!\r\ninterface Vlan1\r\n no ip address\r\n shutdown\r\n!\r\ninterface Vlan10\r\n ip address 10.10.10.1
255.255.255.0\r\n!\r\ninterface Vlan199\r\n ip address 217.21.0.6 255.255.254.0\r\n no ip redirects\r\n ip ospf priority 100\r\n!\r\ninterface Vlan777\r\n ip address 7.7.7.1

Question

Is there a way to change the script so the output is presented line by line way?

Not a solution to your question, but wouldn't `pexpect ` do a much better job than trying to parse raw telnet? — favoretti, Dec 21 '17 at 08:08

score 1 · Accepted Answer · answered Dec 21 '17 at 08:14

The documentation for telnetlib isn't very clear about Telnet.read_very_eager, but it mentions that it reads and writes bytes for other methods. type(s) is probably bytes.

Use bytes.decode to get a string: print(s.decode('ascii')) (use the appropriate encoding)

Note: This is for Python 3.

Muhammad Sohaib · Answer 2 · 2017-12-21T08:23:45.813

-1

You need to check the string with some common special character that separates the lines using python split() function and after that initiate a for loop with the length of variable and then print.

edited Dec 21 '17 at 08:23

answered Dec 21 '17 at 08:10

Muhammad Sohaib

11
5

How can i get telnet output printed line by line?

2 Answers2