Script to poll iptables counters

log.sh

#!/bin/sh

# iptables counter poller
# released under CC0 (public domain)

while true; do
    ((date +%s; \
        iptables -t mangle -x -L FORWARD -vvv -n \
            | tail +3 \
            | awk '{print $2}') \
            | tr '\n' ' '; echo '') >> /var/tmp/log.txt
    sleep 1
done