【整理】ps命令输出字段的含义
Linux中的ps命令，用于查看进程状态信息。
其输出内容有很多列，每一列中又有很多字母或符号表示很多种不同意思。
先贴个例子：
MTLG>ps
PID Uid VSZ Stat Command
1 root 132 S /sbin/init
2 root RWN [ksoftirqd/0]
3 root SW< [events/0]
4 root SW< [khelper]
5 root SW< [kthread]
6 root SW< [kblockd/0]
7 root SW [pdflush]
8 root SW [pdflush]
9 root SW< [kswapd0]
10 root SW< [aio/0]
11 root SW [mtdblockd]
12 root SW< [bfin-spi-master]
13 root SW< [rd_silabs_wq]
14 root DW< [wr_silabs_wq]
15 root SWN [jffs2_gcd_mtd3]
22 root 396 S /bin/sh /root/focus.profile
23 root 32 S /bin/watchdogd -f -k 1 -w 5
30 root SW< [IR_State_Machin]
50 root 11606 S /root/focusapp
51 root 11606 S /root/focusapp
52 root 11606 S /root/focusapp
143 root 11606 S /root/focusapp
144 root 384 S sh -c ps < /dev/silabstty0 > /dev/silabstty0 2>&1
145 root 516 R ps
具体含义为：
字 段 含义
USER 进程所有者的用户名
PID 进程号
%CPU 进程自最近一次刷新以来所占用的CPU时间和总时间的百分比
%MEM 进程使用内存的百分比
VSZ 进程使用的虚拟内存大小，以K为单位
RSS 驻留空间的大小。显示当前常驻内存的程序的K字节数。
TTY 进程相关的终端
STAT 进程状态，用下面的代码中的一个给出：
D 不可中断 Uninterruptible sleep (usually IO)
R 正在运行，或在队列中的进程
S 处于休眠状态
T 停止或被追踪
Z 僵尸进程
W 进入内存交换（从内核2.6开始无效）
X 死掉的进程
< 高优先级
N 低优先级
L 有些页被锁进内存
s 包含子进程
+ 位于后台的进程组；
l 多线程，克隆线程
TIME 进程使用的总CPU时间
COMMAND 被执行的命令行
NI 进程的优先级值，较小的数字意味着占用较少的CPU时间
PRI 进程优先级。
PPID 父进程ID
WCHAN 进程等待的内核事件名
其中关于状态信息的英文解释：
PROCESS STATE CODES
Here are the different values that the s, stat and state output specifiers
(header “STAT” or “S”) will display to describe the state of a process.
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 its parent.
For BSD formats and when the stat keyword is used, additional characters may
be displayed:
< high-priority (not nice to other users)
N low-priority (nice to other users)
L has pages locked into memory (for real-time and custom IO)
s is a session leader
l is multi-threaded (using CLONE_THREAD, like NPTL pthreads do)
+ is in the foreground process group
来自：http://www.crifan.com/order_the_meaning_of_the_ps_command_output_fields/