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 version.
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 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.
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 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. 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 override 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 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.
--version
Display version and source of this program.
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 put in place the appropriate System.map file
when you install a new kernel in order
to get meaningful information from the
WCHAN
field. This should be done every time you compile 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-symbol resolution is:
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).
AUTHOR
ps
was originally written by Branko Lankester <lankeste@fwi.uva.nl>. Michael K.
Johnson <johnsonm@redhat.com> 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 pid-list feature. Charles
Blake <cblake@bbn.com> added multi-level sorting, the dirent-style library, the
device name-to-number 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@redhat.com> is the current maintainer.
