Linux system time many processes running, if they can reasonably manage, you can optimize system performance. In the Linux system, there are five kinds of process status, were run, interrupt, can not be interrupted, and stopped dead, as shown in their respective meanings as follows.
R (running): process is running or waiting in the run queue.
S (Interrupt): the process is sleeping when the conditions for forming a signal is received or, if out of this state.
D (uninterruptible): Process system does not respond to asynchronous signals, even with the kill command nor can it be interrupted.
Z (zombie): the process has been terminated, but the process descriptor remain until the parent calls wait4 () function will process system release.
T (Stop): Stop running after process receives a stop signal.
In the Linux system command parameters are sub-length format, and the format can not be combined length between the long format, it can not be merged between the long and short forms, but between the short and short forms can be combined, consolidated only reserved a - (minus sign) can be. Further parameters ps command can not allow a minus sign (-), and therefore can be directly written ps aux like.