ps命令

Last Updated: 2023-06-24 13:54:12 Saturday

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ps，process statue，用于查看系统进程状态的命令，ps命令显示出来的是系统当前进程及相关信息的一个快照。

如果需要动态显示（不断刷新）进程状态，使用top命令，或者用ps配合watch命令。

-e，显示系统所有当前进程：

$ ps -e     # or -A， standard display syntax
$ ps -ef    # -f, full-format listing
$ ps -eF    # -F, extra full-format
$ ps -elf   # -l, long format，跟多列，含PRI和NI
$ ps -elF
$ ps -elfy  # -y， only used with -l，不显示flag列
$ ps -elFy

-U <username>，按用户（RUID）查询进程：

-u这个参数貌似有问题...EUID和RUID又有什么区别？

-L，显示线程：

LWP（Light Weight Process）列是线程ID，如果进程只有一个线程，此ID同PID
NLWP列显示了某PID的线程数量

对所有进程按CPU使用率进行排序：

$ ps aux --sort pcpu | tail -n5  # from small to big, so tail
$ ps aux | sort -rnk3 | head -n5 # use sort, column 3 is cpu usage info

显示出来的信息还是有些凌乱，主要是CMD列有点长。

对所有进程按MEM占用进行排序：

$ ps aux --sort pmem | tail -n5
$ ps aux | sort -rnk4 | head -n5  # sort column 4

ps aux是BSD风格显示。

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)
I Idle kernel thread
R running or runnable (on run queue)
S interruptible sleep (waiting for an event to complete)
T stopped by job control signal
t stopped by debugger during the tracing
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

本文链接：https://cs.pynote.net/sf/linux/shell/202201101/

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