PS(1)
NAME
ps - report process status
SYNOPSIS
ps [-] [lujsvmaxScewhrnu] [txx] [O[+|-]k1[[+|-]k2...]]
[pids]
there are also three long options:
--sortX[+|-]key[,[+|-]key[,...]]
--help
--version
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
The command-line options for this version of ps are
derived from the BSD version of ps, not the System V ver-
sion.
The command-line arguments should not be preceeded by a
`-' character, because in the future, a `-' will be used
to indicate Unix98-standard command-line arguments, while
no `-' will indicate the current ``extended BSD'' style of
command line arguments.
For now, ps will give you a warning if you use a `-' for a
short option, but it will still work. If you have shell
scripts which use BSD-style arguments to ps, take heed of
the warning and fix them, or else your scripts will fail
to function correctly at some point in the future. If you
want to turn off the warnings, set the I_WANT_A_BROKEN_PS
environment variable.
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 num-
ber 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. To be exact, every w that is specified
will add another possible line to the output. If the
space isn't needed it isn't used. You may up to 100
w's.
h no header
r running procs only
n numeric output for USER and WCHAN.
txx only procs with controlling tty xx; for xx you may
use either the name of a device file under "/dev" or
that name with either tty or cu sliced off. This is
the reverse heuristic that ps uses to print out the
abbreviated tty name in the TT field, e.g. ps -t1.
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 specifica-
tions 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. If pids are given, they are listed
no matter what. If a tty is given matching processes
are listed no matter what. These two features over-
ride the 'a' and 'x' flags.
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 lexico-
graphic 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.
--version
Display version and source of this program.
SORT KEYS
Note that the values used in sorting are the internal val-
ues 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 val-
ues, ... ;-)
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 run-
ning /usr/sbin/psupdate to get meaningful information from
the WCHAN field. This should be done every time you com-
pile a new kernel. You should also run 'ps' as root once
and then any time the tty devices in the "/dev" directory
change.
As of procps-1.00, ps/top read System.map directly if it
is available. The search path for kernel address-to-sym-
bol resolution is:
$PS_SYSTEM_MAP
/boot/System.map-`uname -r`
/boot/System.map
/lib/modules/`uname -r`/System.map
/etc/psdatabase
/boot/psdatabase-`uname -r`
/boot/psdatabase,
/lib/modules/`uname -r`/psdatabase
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 worth-
less.
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).
To perform the device number to name mapping ps maintains
a file called "/etc/psdevtab" (updated whenever "/dev"
becomes newer and permissions allow update). If permis-
sions do not allow update, every invokation of ps requires
a stat(2) of every file in the "/dev" directory. If
"/dev" entries change often on your system, you should run
ps as root often. I may add a fallback file under $HOME
under force of popular demand.
AUTHOR
ps was originally written by Branko Lankester
lt;lankeste@fwi.uva.nl. Michael K. Johnson <johnsonm@red-
hat.com> re-wrote it significantly to use the proc
filesystem, changing a few things in the process. Michael
Shields lt;mjshield@nyx.cs.du.edu added the pid-list fea-
ture. Charles Blake lt;cblake@bbn.com added multi-level
sorting, the dirent-style library, the device name-to-num-
ber mmaped database, the approximate binary search
directly on System.map, and many code and documentation
cleanups. David Mossberger-Tang wrote the generic BFD
support for psupdate. Michael K. Johnson <johnsonm@red-
hat.com> is the current maintainer.
Please send bug reports to lt;procps-bugs@redhat.com