2.1
import telnetlib

router_ip = "192.168.122.169"
username = "admin"
password = "cisco"

tn = telnetlib.Telnet(router_ip)
tn.read_until("Username: ")
tn.write(username + "\n")
tn.read_until("Password: ")
tn.write(password + "\n")
tn.write("terminal length 0\n")

def getConfigFromRouter(config_type):
        tn.write("show " + config_type + "\n")
        tn.read_until("version")
        return set(("version" + tn.expect([".+#$"])[2]).splitlines())

startup_cfg = getConfigFromRouter("startup-config")
running_cfg = getConfigFromRouter("running-config")

diff = running_cfg.difference(startup_cfg)
if(len(diff)>0):
        print("startup-config modified lines:")
        for l in diff:
                print l
        print("\nWas before:")
        for l in startup_cfg.difference(running_cfg):
                print l
else:
        print("startup-config and running-config are the same.")

tn.write("exit\n")
tn.read_all()

2.2**************

import telnetlib

router_ip = "192.168.122.169" # Cisco IOSv15.6(1)T-1 router IP
username = "admin" # telnet login
password = "cisco" # telnet password

cfg_filename = "old_cfg.txt" # old config file

tn = telnetlib.Telnet(router_ip)   # Connecting to a host (router)
tn.read_until("Username: ")        # Reading telnet output until there is Username text
tn.write(username + "\n")          # Sending username and new line symbol (as enter key)
tn.read_until("Password: ")        # Reading telnet output until there is Password text
tn.write(password + "\n")          # Sending pass and new line symbol (as enter key)
tn.write("terminal length 0\n")    #  (to not to pause terminal output)

def getConfigFromRouter(config_type):          # function for reading config from the router
        tn.write("show " + config_type + "\n")  # sending show startup-config or running-config
        tn.read_until("version") # skipping text until version is displayed
        return set(("version" + tn.expect([".+#$"])[2]).splitlines()[:-1])

def compareConfigs(file_config, running):
    diff = file_config.difference(running) # comparing 2 configs
    if(len(diff)>0): # if theres is a diffrence
            print("running-config modified lines:")
            for l in diff: # looping and printing diff
                    print l
            print("\nLines in " + cfg_filename + ":")
            for l in running.difference(file_config):
                    print l
    else: # if theres no diff printing that theres none
            print("config from file (" + cfg_filename + ") and running-config are the same.")

running_cfg = getConfigFromRouter("running-config")
file_cfg = set(open(cfg_filename, "r").read().splitlines()) # opening and reading whole file converting it to lines and to then to set
compareConfigs(file_cfg, running_cfg)

tn.write("exit\n") #sending exit to log out out of the router
tn.read_all()


3**************************************************************************


version 15.6
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R1
!
boot-start-marker
boot-end-marker
!
!
!
no aaa new-model
ethernet lmi ce
!
!
!
mmi polling-interval 60
no mmi auto-configure
no mmi pvc
mmi snmp-timeout 180
!
!
!
!
!
no ip icmp rate-limit unreachable
!
!
!
!
!
!
no ip domain lookup
ip domain name cisco.com
ip cef
no ipv6 cef
!
multilink bundle-name authenticated
!
!
!
!
username admin privilege 15 password 0 cisco
!
redundancy
!
no cdp log mismatch duplex
!
ip tcp synwait-time 5
!
!
!
!
!
!
!
!
!
!
!
!
!
interface GigabitEthernet0/0
 ip address dhcp
 duplex auto
 speed auto
 media-type rj45
!
interface GigabitEthernet0/1
 no ip address
 shutdown
 duplex auto
 speed auto
 media-type rj45
!
interface GigabitEthernet0/2
 no ip address
 shutdown
 duplex auto
 speed auto
 media-type rj45
!
interface GigabitEthernet0/3
 no ip address
 shutdown
 duplex auto
 speed auto
 media-type rj45
!
ip forward-protocol nd
!
!
no ip http server
no ip http secure-server
ip ssh version 2
!
!
!
!
control-plane
!
banner exec ^C
**************************************************************************
* IOSv is strictly limited to use for evaluation, demonstration and IOS  *
* education. IOSv is provided as-is and is not supported by Cisco's      *
* Technical Advisory Center. Any use or disclosure, in whole or in part, *
* of the IOSv Software or Documentation to any third party for any       *
* purposes is expressly prohibited except as otherwise authorized by     *
* Cisco in writing.                                                      *
**************************************************************************^C
banner incoming ^C
**************************************************************************
* IOSv is strictly limited to use for evaluation, demonstration and IOS  *
* education. IOSv is provided as-is and is not supported by Cisco's      *
* Technical Advisory Center. Any use or disclosure, in whole or in part, *
* of the IOSv Software or Documentation to any third party for any       *
* purposes is expressly prohibited except as otherwise authorized by     *
* Cisco in writing.                                                      *
**************************************************************************^C
banner login ^C
**************************************************************************
* IOSv is strictly limited to use for evaluation, demonstration and IOS  *
* education. IOSv is provided as-is and is not supported by Cisco's      *
* Technical Advisory Center. Any use or disclosure, in whole or in part, *
* of the IOSv Software or Documentation to any third party for any       *
* purposes is expressly prohibited except as otherwise authorized by     *
* Cisco in writing.                                                      *
**************************************************************************^C
!
line con 0
 exec-timeout 0 0
 privilege level 15
 logging synchronous
line aux 0
 exec-timeout 0 0
 privilege level 15
 logging synchronous
line vty 0 3
 login
 transport input none
line vty 4
 login local
 transport input all
!
no scheduler allocate
!
end