ps Process Status

进程5种状态

R 运行 runnable (on run queue)  正在运行或在运行队列中等待
S 中断 sleeping  休眠中, 受阻, 等待某个条件的形成或接受到信号
D 不可中断 uninterruptible sleep (usually IO)   
Z 僵死  zombie  进程已终止, 但进程描述符存在, 直到父进程调用wait4()系统调用后释放
T 停止 traced or stopped  (进程收到SIGSTOP, SIGSTP, SIGTIN, SIGTOU信号后停止运行)


Note that "ps -aux" is distinct from "ps aux". 
The POSIX and UNIX standards require that "ps -aux" print all processes owned by a user named "x", 
as well as printing all processes that would be selected by the -a option. 
If the user named "x" does not exist, this ps may interpret the command as "ps aux" instead and print a warning. 

ps aux 和 ps -ef 
两者的输出结果差别不大，但展示风格不同。
aux是BSD风格，-ef是System V风格。 
aux会截断command列，而-ef不会。

ps aux |wc -l
102
ps -ef |wc -l
104
ps -ef |grep java

推荐使用  ps -ef