Web Hosting Tutorials

ps command in depth

Posted on October 12th, 2006 by Admin.
Categories: Cpanel Hosting, Linux.

ps command in detail

Here are the possible codes when using state “$ ps -e -o state,cmd”

PROCESS STATE CODES
D uninterruptible sleep (usually IO)
R runnable (on run queue)
S sleeping
T traced or stopped
Z a defunct (”zombie”) process
< 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

For instance:

Note that the -o is for user defined, and -e is for select all process.

$ ps -e -o pid,state,start,time,etime,cmd

…
9946 S 15:40:45 00:00:00 02:23:29 /bin/bash -i
9985 T 15:41:24 00:00:01 02:22:50 vi manual
10320 T 17:38:42 00:00:00 25:32 vi test.c
…

You may want to command below, without the -e, which will give the process only under the current terminal.

$ ps -o pid,state,start,time,etime,cmd

To Check cause of Load on Server ..

$ ps -e -o %cpu,pid,state,start,time,etime,%cpu,%mem,cmd|sort -rn|less

$ ps aux

USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
root 1 0.0 0.0 1380 480 ? S Aug04 0:00 init [3]
root 2 0.0 0.0 0 0 ? SWN Aug04 0:00 [ksoftirqd/0]
root 3 0.0 0.0 0 0 ? SW< Aug04 0:00 [events/0]
root 4 0.0 0.0 0 0 ? SW< Aug04 0:00 [khelper]
...

Or, if you want to see the environment add the -e option

$ ps aeux

…
kyle 2735 0.0 0.1 4400 1492 pts/0 S Aug04 0:00 -bash USER=kyle LOGNAME=kyle HOME=/home/kyle PATH=/usr/
kyle 2771 0.0 0.0 4328 924 pts/0 S Aug04 0:00 screen -e^Pa -D -R HOSTNAME=third-fl-71.localdomain TERM=xterm S
kyle 2772 0.0 0.6 9476 6352 ? S Aug04 0:54 SCREEN -e^Pa -D -R HOSTNAME=third-fl-71.localdomain TERM=xterm S
kyle 2773 0.0 0.1 4432 1548 pts/1 S Aug04 0:10 /bin/bash STY=2772.pts-0.third-fl-71 TERM=screen TERMCAP=SC|scre
kyle 2797 0.0 0.1 4416 1496 pts/2 S Aug04 0:00 /bin/bash STY=2772.pts-0.third-fl-71 TERM=screen TERMCAP=SC|scre
…
There is also a -f “forrest” option. Also note below ” -bash” is the start of a login shell.

$ ps aeuxwwf

The ww option above gives a wide format with all variables. Use the above command if you plan to parse through a Perl script. Otherwise, it may be easier to do a quick read using the command below, without “ww”.

$ ps aeuxf

…
root 2339 0.0 0.1 3512 1444 ? S Dec01 0:00 /usr/sbin/sshd
root 25651 0.0 0.1 6764 1980 ? S Dec23 0:00 \_ /usr/sbin/sshd
kyle 25653 0.0 0.2 6840 2236 ? S Dec23 0:14 \_ /usr/sbin/sshd
kyle 25654 0.0 0.1 4364 1440 pts/4 S Dec23 0:00 \_ -bash USER=kyle LOGNAME=kyle HOME=/home/kyle
kyle 25690 0.0 0.0 4328 920 pts/4 S Dec23 0:00 \_ screen -e^Pa -D -R HOSTNAME=third-fl-71.localdomain TERM=xterm
root 2355 0.0 0.0 2068 904 ? S Dec01 0:00 xinetd -stayalive -pidfile /var/run/xinetd.pid
…

It is also possible to list the process by command line. For example, the following command will only list the vi processes.

$ ps -fC vi
UID PID PPID C STIME TTY TIME CMD
kyle 5049 5020 0 May11 pts/13 00:00:00 vi -nw Notes
kyle 12368 5104 0 May12 pts/18 00:00:00 vi -nw dnotify.c
kyle 19792 18028 0 May13 pts/20 00:00:00 vi -nw hello.c
kyle 14034 27367 0 18:52 pts/8 00:00:00 vi -nw 1.txt

You may also want to consider using top in batch mode. Here the “-n 1″ means refresh once, and the “b” is for batch. The “fmt -s” is to put it in a more readable format.

$ top -n 1 b |fmt -s >>statfile

Enjoy

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