I used to have trouble with processes blocking ports while developing. I would type up a number of commands trying to find the pid of the process that’s blocking the port and kill that process. It was rather frustrating. Eventually I took the commands and wrote a script that kills processes based on the port that it’s using.

You run it with ./kill_script_by_port.sh with the port number as an argument.

The first line uses the lsof command to get the processes using that port. For example lsof -i:52639 outputs the following on my machine

This output gets piped into awk which gets the 2nd word of every line. grep removes the PID word. Finally sort -u removes any duplicate PIDs.

The rest of the code reads the PIDs into an array and loops through them killing all the processes that use the port.

If there’s a particular process you know you don’t want to kill, you can put the command for the process as an argument to grep -v -e before the awk in the pipeline. That process will be removed from the lsof output.