Scan a range with nmap.

gistfile1.txt

#!/usr/bin/python2
#
# DEPS: nmap, notify-send
#

import subprocess
import re
import time
import sys
import os
  
def diff(list1, list2):
  if len(list1) < len(list2):
    tmp = list2
    list2 = list1
    list1 = tmp
  tmp = []
  for e in list1:
    if e not in list2:
      tmp.append(e)
  return tmp


# help screen
if len(sys.argv) != 3:
  print '\n\t################   LAN OBSERVER   ################'
  print '\trun as root for better results \'nmap -sn\' :) '
  print '\tusage:\t\t%s \'ip range\' \'intervall\' [sec] '%(sys.argv[0])
  print '\texample:\t%s 192.168.1.1-10 15'%(sys.argv[0])
  print '\t\t\twill scan every 15 sec the IP Range 192.168.1.1-10\n'
  print '\t##################################################\n\n'
  sys.exit()

iprange = sys.argv[1]
intervall = float(sys.argv[2])

nmap = ['nmap', '-sn', iprange]
tmpList = []
hostList = []
user = os.getlogin()

notify_send_join = 'notify-send \'host join: %s\''
notify_send_quit = 'notify-send \'host quit: %s\'' 

if os.getuid() == 0:
    notify_send_join = 'su - '+user+' -c \"notify-send \'host join: %s\'\"'
    notify_send_quit = 'su - '+user+' -c \"notify-send \'host quit: %s\'\"'


try:
  while True:
    output = subprocess.Popen(nmap, stdout=subprocess.PIPE).stdout.read()
    tmpList = re.findall('\d*\.\d*\.\d*\.\d*', output)
    
    if tmpList == hostList:
      pass
    elif len(tmpList) >= len(hostList):
      for ip in tmpList:
        if ip not in hostList:
          hostList.append(ip)
          os.system(notify_send_join%(ip))
    else:
      for ip in diff(hostList, tmpList):
        hostList.remove(ip)
        os.system(notify_send_quit%(ip))

    time.sleep(intervall)
    #print hostList
    
except(KeyboardInterrupt):
  print 'KeyboardInterrupt'
  sys.exit()