Little Python script to dump IP addresses from a file

grepips.py

#!/usr/bin/python3
import sys, re

f = open(sys.argv[1],'r')
text = f.read()
ips = [] 
regex = re.findall(r'\b(?:\d{1,3}\.){3}\d{1,3}\b',text)
if regex is not None:
    for match in regex:
        if match not in ips:
            ips.append(match)
            print(match)