How to kill a process in MacOS?

If you're trying to kill -9 it, you have the correct PID, and nothing happens, then you don't have permissions to kill the process.

Solution:

$ sudo kill -9 PID

Okay, sure enough Mac OS/X does give an error message for this case:

$ kill -9 196
-bash: kill: (196) - Operation not permitted

So, if you're not getting an error message, you somehow aren't getting the right PID.

Some cases you might want to kill all the process running in a specific port. For example, if I am running a node app on 3000 port and I want to kill that and start a new one; then I found this command useful.

Find the process IDs running on TCP port 3000 and kill it

kill -9 `lsof -i TCP:3000 | awk '/LISTEN/{print $2}'`

If you know the process name you can use:

killall Dock

If you don't you can open Activity Monitor and find it.

I just now searched for this as I'm in a similar situation, and instead of kill -9 698 I tried sudo kill 428 where 428 was the pid of the process I'm trying to kill. It worked cleanly for me, in the absence of the hyphen '-' character. I hope it helps!