EDITED:These are the the only most commonly used (and important) ps command options I've come across so far: $ ps ux, $ ps au, $ ps aux, $ ps U aahan, $ ps uU aahanSo, is that all, or am I missing 1 or 2?Can someone tell me the difference between $ ps au and $ ps aux?
Frequently used ps (process status) commands in linux?
ps
My most common is ps xuwww which shows the complete width of the command.  Another common one I use is ps xo pid,ppid,cmd which just shows the process id, the parent's process id and the command string.You ask the difference between ps au and ps aux.  The x options shows processes that are not attached to a terminal; generally daemons or disowned, background processes.  This is very useful when you want to check the status of a daemon (like tomcat or httpd) or the status of an application started from the window manager (which will not have a terminal associated with it).