Subdomains Scanner

#Subdomains Grabber
#By INJ3CTOR_M4 // facebook.com/H4ck19

import re, urllib2, socket, os, sys
from urlparse import urlparse
from platform import system

if system() == 'Linux':
    os.system('clear')
if system() == 'Windows':
    os.system('cls')

def Bing_sub(domain):
    alldomains = []
    i = 1
    while True:
        bing = urllib2.urlopen('http://www.bing.com/search?q=domain:'+domain+'&first='+str(i)+'&go=&filt=all&FORM=PERE2').read()
        data = re.findall('<h2><a href="(.*?)"', bing)
        for domains in data:
            domains = urlparse(domains)
            alldomains.append(domains.netloc.replace('www.', ''))
        i+=10
        if not re.search('class="sb_pagN"', bing):
            break
    return list(set(alldomains))

try:
    domain = sys.argv[1]
    os.unlink('subdomains.txt')
    i = 0
    for b in Bing_sub(domain):
        print (b+' : '+socket.gethostbyname(b))
        subdomains = open('subdomains.txt', 'ab')
        subdomains.write('http://'+b+'\r\n')
        subdomains.close()
        i+=1
    print 'Number of Subdomains : '+str(i)
except IndexError:
    print '\t\tUsage: python '+sys.argv[0]+' [site.com]\n'