reading output from pexpect sendline

Question

I have pexpect working, but I am having problems printing the output back from it. In my test script below, it creates the ssh connection, and then sends a sudo su -, then my password, and then sends a line that would require sudo access to do (I have also added p.interact() a few times to make sure it is at root). The problem I am having, is with returning the output of the commands I run. In the end I am wanting to run some top commands, and some du -h, and other(much more complex) space commands. But currently when it tries to print p.before, I get:

Traceback (most recent call last):
File "./ssh.py", line 37, in <module>
print p.before()
TypeError: 'str' object is not callable

Here is the script I am working from(edited to remove my pass and such)

#!/usr/bin/env python

import pexpect
import struct, fcntl, os, sys, signal

def sigwinch_passthrough (sig, data):
    # Check for buggy platforms (see pexpect.setwinsize()).
    if 'TIOCGWINSZ' in dir(termios):
        TIOCGWINSZ = termios.TIOCGWINSZ
    else:
        TIOCGWINSZ = 1074295912 # assume
    s = struct.pack ("HHHH", 0, 0, 0, 0)
    a = struct.unpack ('HHHH', fcntl.ioctl(sys.stdout.fileno(), TIOCGWINSZ , s))
    global global_pexpect_instance
    global_pexpect_instance.setwinsize(a[0],a[1])

ssh_newkey = 'Are you sure you want to continue connecting'
p=pexpect.spawn('ssh user@localhost')
i=p.expect([ssh_newkey,'password:',pexpect.EOF,pexpect.TIMEOUT],1)
if i==0:
    print "I say yes"
    p.sendline('yes')
    i=p.expect([ssh_newkey,'password:',pexpect.EOF])
if i==1:
    print "I give password",
    p.sendline("mypassword")
elif i==2:
    print "I either got key or connection timeout"
    pass
elif i==3: #timeout
    pass
global global_pexpect_instance
global_pexpect_instance = p
p.sendline("sudo su -")
p.sendline("mypasswd")
p.sendline("mkdir /home/user/test")
print p.before

I am working off of this link: http://linux.byexamples.com/archives/346/python-how-to-access-ssh-with-pexpect/

Any help is much appreciated.

EDIT: As Armin Rigo pointed out below. I was calling to p.before as a function like p.before(). Stupid mistake on my part, as this explains why I was getting this error today, and not yesterday when I was trying this. After making that change to my script, and modifying the command being sent, print p.before, and no output is returned. Any other ways to return output from a sendline() command?

Answer 1

Use logfile, that logfile is store all output in terminal.use that example code:-

child = pexpect.spawn("ssh user@localhost")
child.logfile = open("/tmp/mylog", "w")
child.expect(".*assword:")
child.send("guest\r")
child.expect(".*\$ ")
child.sendline("python -V\r")

open the log file and see everything in terminals event