ps -ef |grep firefox
rinzwind  5046  1484 48 19:52 ?        00:00:01 /usr/lib/firefox/firefox
rinzwind  5113  4992  0 19:52 pts/4    00:00:00 grep --color=auto firefox

kill -9 5046
~$ ps -ef |grep firefox
rinzwind  5148  4992  0 19:54 pts/4    00:00:00 grep --color=auto firefox