telnetlib errors with read_until

Question

I'm very new to python scripting, but I thought I would give it a go to see if I can automate a few simple tasks I preform regularly over Telnet.

I found a basic python telnet script:

import getpass
import sys
import telnetlib

HOST = "localhost"
user = raw_input("Enter your remote account: ")
password = getpass.getpass()

tn = telnetlib.Telnet(HOST)

tn.read_until("login: ")
tn.write(user + "\n")
if password:
    tn.read_until("Password: ")
    tn.write(password + "\n")

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

print tn.read_all()

This 'seems' to work, but returns nothing to the console. Since the login process takes a few seconds, I figure it's just going too fast & needs to wait for the user prompt. So I tried adding this.

tn.read_until(">")

It does not work... I get this error

  File "test.py", line 16, in <module>
    tn.read_until(">")
  File "/usr/lib/python2.7/telnetlib.py", line 319, in read_until
    return self.read_very_lazy()
  File "/usr/lib/python2.7/telnetlib.py", line 395, in read_very_lazy
    raise EOFError, 'telnet connection closed'
EOFError: telnet connection closed

I feel like I'm missing something simple... but the solution seems to be alluding me. Any input will be highly appreciated!

maybe you need to send `\r\n` instead of `\n`, you can confirm with wireshark — Uku Loskit, Aug 31 '13 at 12:35
This did it! I replaced \n with \r and it seems to be working a treat now! — user2735454, Aug 31 '13 at 13:05

score 0 · Answer 1 · edited May 23 '17 at 10:31

0

Check if this link - it may help you out. I guess you may want to specify

tn.write("vt100\n")

before printing out anything.

edited May 23 '17 at 10:31

Community

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answered Aug 31 '13 at 13:00

Prahalad Deshpande

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score 0 · Accepted Answer · answered Aug 31 '13 at 13:07

0

You may have to use another line separator depending on the platform. try \r or \r\n

answered Aug 31 '13 at 13:07

Uku Loskit

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telnetlib errors with read_until

2 Answers2