[ SCR ] LAN IPs discovery with python using nmap

landisc.py

#!/usr/bin/python3

# List all hosts' IP adresses in the
# local network reachable by nmap -sn

import os
import re
import sys

if __name__ == "__main__":

    addresses = []

    # ip from first arg or default
    IP = sys.argv[1] if len(sys.argv) > 1 else '192.168.0.0'

    # a regex pattern for ip addresses
    re_pattern = r'\b25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?\.25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?\.25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?\.25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?\b'

    # runs nmap
    nmap_result = os.popen('nmap -sn ' + IP + '/24 | grep \'Nmap scan report\'').read().splitlines()

    # extracts all ips in response
    for i, line in enumerate(nmap_result):
        filtered = re.findall(r'[0-9]+(?:\.[0-9]+){3}', line)
        filtered = re.findall(re_pattern, line)
        addresses.append('.'.join(filtered))

    # output
    for addr in addresses:
        print(addr)

    exit(0)