Collapses subnets and/or IPs into the smallest possible set of subnets

collapse-nets.py

#!/usr/bin/env python3
# Collapses subnets and/or IPs into the smallest possible set of subnets
import sys
import ipaddress

if len(sys.argv) != 2:
    print("Usage: {} <file>".format(sys.argv[0]))
    sys.exit(-1)

with open(sys.argv[1]) as f:
    nets = set()
    for line in f.readlines():
        line = line.strip()

        nets.add(ipaddress.ip_network(line))

    collapsed = list(ipaddress.collapse_addresses(nets))
    for subnet in collapsed:
        print(subnet)