确定在特定端口上侦听的进程 pid

netstat -nlp should tell you the PID of what's listening on which port.

The -p flag of netstat gives you PID of the process:

netstat -l -p

*use sudo if showing - instead of PID

Edit: The command that is needed to get PIDs of socket users in FreeBSD is sockstat. As we worked out during the discussion with @Cyclone, the line that does the job is:

sockstat -4 -l | grep :80 | awk '{print $3}' | head -1

Short version which you can pass to kill command:

lsof -i:80 -t

netstat -p -l | grep $PORT and lsof -i :$PORT solutions are good but I prefer fuser $PORT/tcp extension syntax to POSIX (which work for coreutils) as with pipe:

pid=`fuser $PORT/tcp`

it prints pure pid so you can drop sed magic out.

One thing that makes fuser my lover tools is ability to send signal to that process directly (this syntax is also extension to POSIX):

$ fuser -k $port/tcp       # with SIGKILL
$ fuser -k -15 $port/tcp   # with SIGTERM
$ fuser -k -TERM $port/tcp # with SIGTERM

Also -k is supported by FreeBSD: http://www.freebsd.org/cgi/man.cgi?query=fuser

Since sockstat wasn't natively installed on my machine I hacked up stanwise's answer to use netstat instead..

netstat -nlp | grep -E "[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\:2000" | awk '{print $7}' | sed -e "s/\/.*//g""

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.

on windows, the netstat option to get the pid's is -o and -p selects a protocol filter, ex.: netstat -a -p tcp -o

Syntax:

kill -9 $(lsof -t -i:portnumber)

Example: To kill the process running at port 4200, run following command

kill -9 $(lsof -t -i:4200)

Tested in Ubuntu.