I always want to kill a process id which listening on Port 3000.
So presently I am using,

1.lsof -i tcp:3000

will give output as,

COMMAND  PID   USER   FD   TYPE DEVICE SIZE/OFF NODE NAME

ruby    6697   xxxx   5u  IPv4 251982      0t0  TCP *:3000 (LISTEN)

and I will kill the PID using,

2. kill -9 6697

I want to create a bash program which do this process automatically.

I tried using xargs to get PID of the output of first command but failed.