Kill what ever is running on port 8080

1. Find out what Process ID (pid) is using the required port (e.g port 5434).

   ps aux | grep 5434
   

2. Kill that process:

   kill -9 <pid>
   

lsof -i @localhost:8080

kill -9 <<PID>>

Turns out it's just kill -9 PID, you might need sudo. Found the answer on maclife.com in the article Terminal 101: Track and Kill Processes.