I wanted to programmatically -- using only Bash -- kill the process listening on a given port.
Let's say the port is 8089, then here is how I did it:
badPid=$(netstat --listening --program --numeric --tcp | grep "::8089" | awk '{print $7}' | awk -F/ '{print $1}' | head -1)
kill -9 $badPid
I hope this helps someone else! I know it is going to help my team.