-ef shows you the parent pid which aux doesn't. My usage for ps tends to be to get pid information so I can kill processes with it. When a misbehaving parents s

-ef shows you the parent pid which aux doesn't. My usage for ps tends to be to get pid information so I can kill processes with it. When a misbehaving parents spawns a lot of children easier to kill the parent. I use 'w' command if I want CPU info.