#!/usr/bin/env python

import subprocess
import re

#function to find gateway IP using subprocess and regex
def get_gateway():
    get_route = subprocess.check_output(["ip route"], shell=True)
    gateway_result = re.search(r"(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]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)", str(get_route))
    return gateway_result.group(0)

gateway = get_gateway()
print(gateway)