Extract unique IPs from live tcpdump capture

Question

I am using the following command to output IPs from live tcpdump capture

sudo tcpdump -nn -q ip -l | awk \'{print $3; fflush(stdout)}\' >> ips.txt
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Answer 1

While I'm a huge Awk fan, it's worthwhile having alternatives. Consider this example using cut:

  tcpdump -n ip | cut -d ' ' -f 3 | cut -d '.' -f 1-4 | sort | uniq