I am learning pexpect and regular expressions. I have two questions: 1. Does child.expect(some text here) actually have to be a regular expression? 2. If anyone could tell my why my script hangs on password entry, it would be greatly appreciated.
import pexpect
import getpass
import sys
try:
switch = raw_input("Host: ")
un = raw_input("Username: ")
pw = getpass.getpass("Password: ")
child = pexpect.spawn("ssh %s@%s" % (un, switch))
child.logfile = sys.stdout
selection = child.expect(['Are you sure you want to continue connecting (yes/no)?','login as:'])
if selection == 0:
child.sendline("yes")
elif selection == 1:
i = child.expect(['login as:','[email protected]\'s password:'])
if i == 0:
child.sendline(un)
elif i == 1:
child.sendline(pw)
child.expect('Switch#')
child.sendline("show cdp nei")
except Exception as e:
print("Failed on login")
print(e)
From the docs:
… The pattern can be a StringType, EOF, a compiled re, or a list of any of those types. Strings will be compiled to re types. …
So, if you pass a pattern like this:
['Are you sure you want to continue connecting (yes/no)?','login as:']
… that's a list of two strings, which will both be compiled to regular expressions. So, e.g., you'll have a capturing group containing the single value yes/no, appearing 0 or 1 times, which probably isn't very useful.
If you want to match them as literal strings, the simplest thing to do is probably call re.escape on them:
[re.escape('Are you sure you want to continue connecting (yes/no)?'),
re.escape('login as:')]