Cara Memeriksa ID Proses di Linux

$ ps ax | grep firefox
2222 ?        S      0:00 /bin/sh /usr/lib/firefox-3.6.9/firefox
2231 ?        Sl   514:36 /usr/lib/firefox-3.6.9/firefox-bin
30290 pts/2    S+     0:00 grep --color=auto firefox
Adventurous Albatross