gistfile1.txt

#!/usr/bin/env python

import threading, paramiko

cmd = "someCommand"

outlock = threading.Lock()

def workon(host):
    try:
        ssh = paramiko.SSHClient()
        ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
        ssh.connect(host, username='someUser', password='somePass')
        stdin, stdout, stderr = ssh.exec_command(cmd)
        stdin.write('xy\n')
        stdin.flush()
        with outlock:
            print host
            print stdout.readlines()
    except paramiko.AuthenticationException:
            print "FAIL" + host

def main():
    hosts = open('hosts.txt')
    threads = []
    for h in hosts:
        h = h.rstrip()
        t = threading.Thread(target=workon, args=(h,))
        t.start()
        threads.append(t)
    for t in threads:
        t.join()

main()