ps aux : 프로세스 상태를 보는 용도 ps -ef : 부모 프로세스와 자식 프로세스의 관계를 볼 때 D Uninterruptible sleep (usually IO) R Running or runnable (on run queue) S Interruptible sleep (waiting for an event to complete) T Stopped, either by a job control signal or because it is being traced. W paging (not valid since the 2.6.xx kernel) X dead (should never be seen) Z Defunct ("zombie") process, terminated but not reaped by i..