Merge CIDR blocks into super blocks if possible

cidr.py

#!/usr/bin/env python
#
# Example 1: All blocks in list.txt, one CIDR per line
#   cat list.txt | cidr.py
#
# Example 2: Echo CIDR blocks to stdout
#   echo 1.2.3.0/25 1.2.3.128/25 | cidr.py

import sys
from netaddr import *

# Read from stdin
data = sys.stdin.readlines()

if len(data) == 1:
    # Input from echo
    data = data[0].split()

# Create an IPSet of the CIDR blocks
# IPSet automatically runs cidr_merge
nets = IPSet(data)

# Output the superset of CIDR blocks
for cidr in nets.iter_cidrs():
    print cidr

Good thing about gists we relay into the wild is how useful they can be for someone else entirely years later. Hit this lovely simple solution, cloned, 3m later problem solved.

Thank you.

My pleasure 🤩