how do I extract the PID from the output of `lsof -i:8080`?

Question

Each time I need to stop the process that is occupying port 8080, I have to run this command first

$ lsof -i:8080

to get the PID

COMMAND  PID   USER   FD   TYPE  DEVICE SIZE/OFF NODE NAME
python  4024 ubuntu    3u  IPv4 2181080      0t0  TCP *:http-alt (LISTEN) 

and then I kill the PID

kill 4024

I'd like to write a script to make it simple, how do I extract the PID from the output of lsof -i:8080?

Answer 1

You can pipe the lsof -i:8080 output to awk to get the PID:

lsof -i:8080 | awk 'NR==2 {print $2}'

You can then combine it with kill:

kill $(lsof -i:8080 | awk 'NR==2 {print $2}')

You can also create a Bash function and add it at the end of your .bashrc:

function kill8080()
{
    kill $(lsof -i:8080 | awk 'NR==2 {print $2}')
}

I named the above function kill8080, but you can name it as you wish.