Take a list of IPs and turn into a BPF filter

ips2bpf.py

#!/usr/bin/python
# convert a list of IPs to an OR bpf filter
import sys
if len(sys.argv) == 2 and sys.argv[1] != '-':
    f = open(sys.argv[1])
else:
    f = sys.stdin

ips = [s.strip() for s in f.readlines()]
bpf = "( host " + " or host ".join(ips) + ")"
print bpf