1#!/bin/bash 2 3filter_expression="tcp port 80" 4 5net_card="$(ip route get 8.8.8.8 | awk '{ print $5; exit }')" 6 7tcpdump -i "$net_card" $filter_expression -w packets.pcap & 8tcpdump_pid=$! 9 10sleep 60 11 12kill $tcpdump_pid 13