netstat

Find the process used the specific port

netstat -anp|grep 8080

root@pjq:~# netstat -anpl|grep 8080
tcp        0      0 127.0.0.1:8080          0.0.0.0:*               LISTEN      26062/sshd: root
tcp6       0      0 ::1:8080                :::*                    LISTEN      26062/sshd: root
root@pjq:~# kill 26062

http://colinharrington.net/blog/2010/12/which-process-has-that-port-open-linux-netstat-anp/