PS(1)

NAME
ps - report process status

SYNOPSIS
ps [-][lujsvmaxScewhrnu][txx][O[+|-]k1[[+|-]k2...]][pids] there are also two long options: --sortX[+|-]key[,[+|-]key[,...]] --help More long options are on the way...

DESCRIPTION
ps gives a snapshot of the current processes. If you want a repetitive update of this status, use top. This man page documents the /proc-based version of ps, or tries to.

COMMAND-LINE OPTIONS
Command line arguments may optionally be preceeded by a '-', but there is no need for it. There are also some "long options" in GNU style; see below for those.

l   long format

u   user format: gives user name and start time

j   jobs format: pgid sid

s   signal format

v   vm format

m   displays memory info (combine with p flag to get number of pages).

f   "forest" family tree format for command line

a   show processes of other users too

x   show processes without controlling terminal

S   add child cpu time and page faults

c   command name from task_struct

e   show environment after command line and ` + '

w   wide output: don't truncate command lines to fit on one line.

h   no header

r   running procs only

n   numeric output for USER and WCHAN.

txx only procs with controlling tty xx; use for xx the same letters as shown in the TT field. The tty name must be given immediately after the option, with no intervening space, e.g. ps -tv1.

O[+|-]k1[,[+|-]k2[,...]]
    Order the process listing according to the multi-level sort specified by the sequence of short keys from SORT KEYS, k1, k2, ... Default order specifications exist for each of the various formats of ps. These are over-ridden by a user specified ordering. The `+' is quite optional, merely re-iterating the default direction on a key. `-' reverses direction only on the key it precedes. As with t and pids, the O option must be the last option in a single command argument, but specifications in successive arguments are catenated.

pids
    List only the specified processes; they are comma-delimited. The list must be given immediately after the last option in a single command-line argument, with no intervening space, e.g. ps -j1,4,5. Lists specified in subsequent arguments are catenated, e.g. ps -l 1,2 3,4 5 6 will list all of the processes 1-6 in long format.

LONG COMMAND-LINE OPTIONS
These options are preceeded by a double-hyphen.

--sortX[+|-]key[,[+|-]key[,...]]
    Choose a multi-letter key from the SORT KEYS section. X may be any convenient separator character. To be GNU-ish use `='. The `+' is really optional since default direction is increasing numerical or lexicographic order. E.g.: ps -jax --sort=uid,-ppid,+pid

--help
    Get a help message that summarizes the usage and gives a list of supported sort keys. This list may be more up to date than this man page.

SORT KEYS
Note that the values used in sorting are the internal values ps uses and not the `cooked' values used in some of the output format fields. If someone wants to volunteer to write special comparison functions for the cooked values, ... ;-) SHORT LONG DESCRIPTION c cmd simple name of executable C cmdline full command line f flags flags as in long format F field g pgrp process group ID G tpgid controlling tty process group ID j cutime cumulative user time J cstime cumulative system time k utime user time K stime system time m min_flt number of minor page faults M maj_flt number of major page faults n cmin_flt cumulative minor page faults N cmaj_flt cumulative major page faults o session session ID p pid process ID P ppid parent process ID r rss resident set size R resident resident pages s size memory size in kilobytes S share amount of shared pages t tty the minor device number of tty T start_time time process was started U uid user ID number u user user name v vsize total VM size in bytes y priority kernel scheduling priority

FIELD DESCRIPTIONS

PRI This is the counter field in the task struct. It is the time in HZ of the process's possible timeslice.

NI  Standard unix nice value; a positive value means less cpu time.

SIZE
    Virtual image size; size of text+data+stack.

RSS Resident set size; kilobytes of program in memory.

WCHAN
    Name of the kernel function where the process is sleeping, with the `sys_' stripped from the function name. If /etc/psdatabase does not exist, it is just a hex number instead.

STAT
    Information about the status of the process. The first field is R for runnable, S for sleeping, D for uninterruptible sleep, T for stopped or traced, or Z for a zombie process. The second field contains W if the process has no resident pages. The third field is N if the process has a positive nice value (NI field).

TT  Controlling tty.

PAGEIN
    Number of major page faults (page faults that cause pages to be read from disk, including pages read from the buffer cache).

TRS Text resident size.

SWAP
    Kilobytes (or pages if -p is used) on swap device.

SHARE
    Shared memory.

UPDATING
This proc-based ps works by reading the files in the proc filesystem, mounted on /proc. This ps does not need to be suid kmem or have any privileges to run. Do not give this ps any special permissions.

You will need to update the /etc/psdatabase file by running /etc/psupdate to get meaningful information from the WCHAN field. This should be done every time you compile a new kernel.

NOTES
The member used_math of task_struct is not shown, since crt0.s checks to see if math is present. This causes the math flag to be set for all processes, and so it is worthless.

Programs swapped out to disk will be shown without command line arguments, and unless the c option is given, in parentheses.

%CPU shows the cputime/realtime percentage. It will not add up to 100% unless you are lucky. It is time used divided by the time the process has been running.

The SIZE and RSS fields don't count the page tables and the task_struct of a proc; this is at least 12k of memory that is always resident. SIZE is the virtual size of the proc (code+data+stack).

BUGS
Tty names are hard coded: virtual consoles are v1, v2, ... serial lines are s0 and s1, pty's are pp0, pp1 ..., pq0, pq1, ....

AUTHOR
ps was originally written by Branko Lankester (lankeste@fwi.uva.nl) Michael K. Johnson (johnsonm@sunsite.unc.edu) re-wrote it significantly to use the proc filesystem, changing a few things in the process. Michael Shields (mjshield@nyx.cs.du.edu) added the multiple-pids feature. Charles Blake(cblake@ucsd.edu) added multi-level sorting and is the current maintainer of the proc-ps suite.