PS

PS(1)                           User Commands                          PS(1)

NAME

ps – report a snapshot of the current processes.

SYNOPSIS

ps [options]

DESCRIPTION

ps displays information about a selection of the active processes.
If you want a repetitive update of the selection and the displayed
information, use top(1) instead.

This version of ps accepts several kinds of options:

1   UNIX options, which may be grouped and must be preceded by a
dash.
2   BSD options, which may be grouped and must not be used with a
dash.
3   GNU long options, which are preceded by two dashes.

Options of different types may be freely mixed, but conflicts can
appear.  There are some synonymous options, which are functionally
identical, due to the many standards and ps implementations that this
ps is compatible with.

Note that “ps -aux” is distinct from “ps aux”.  The POSIX and UNIX
standards require that “ps -aux” print all processes owned by a user
named “x”, as well as printing all processes that would be selected
by the -a option.  If the user named “x” does not exist, this ps may
interpret the command as “ps aux” instead and print a warning.  This
behavior is intended to aid in transitioning old scripts and habits.
It is fragile, subject to change, and thus should not be relied upon.

By default, ps selects all processes with the same effective user ID
(euid=EUID) as the current user and associated with the same terminal
as the invoker.  It displays the process ID (pid=PID), the terminal
associated with the process (tname=TTY), the cumulated CPU time in
[DD-]hh:mm:ss format (time=TIME), and the executable name (ucmd=CMD).
Output is unsorted by default.

The use of BSD-style options will add process state (stat=STAT) to
the default display and show the command args (args=COMMAND) instead
of the executable name.  You can override this with the PS_FORMAT
environment variable. The use of BSD-style options will also change
the process selection to include processes on other terminals (TTYs)
that are owned by you; alternately, this may be described as setting
the selection to be the set of all processes filtered to exclude
processes owned by other users or not on a terminal.  These effects
are not considered when options are described as being “identical”
below, so -M will be considered identical to Z and so on.

Except as described below, process selection options are additive.
The default selection is discarded, and then the selected processes
are added to the set of processes to be displayed.  A process will
thus be shown if it meets any of the given selection criteria.

EXAMPLES

To see every process on the system using standard syntax:
ps -e
ps -ef
ps -eF
ps -ely

To see every process on the system using BSD syntax:
ps ax
ps axu

To print a process tree:
ps -ejH
ps axjf

To get info about threads:
ps -eLf
ps axms

To get security info:
ps -eo euser,ruser,suser,fuser,f,comm,label
ps axZ
ps -eM

To see every process running as root (real & effective ID) in user
format:
ps -U root -u root u

To see every process with a user-defined format:
ps -eo pid,tid,class,rtprio,ni,pri,psr,pcpu,stat,wchan:14,comm
ps axo stat,euid,ruid,tty,tpgid,sess,pgrp,ppid,pid,pcpu,comm
ps -Ao pid,tt,user,fname,tmout,f,wchan

Print only the process IDs of syslogd:
ps -C syslogd -o pid=

Print only the name of PID 42:
ps -q 42 -o comm=

SIMPLE PROCESS SELECTION

a      Lift the BSD-style “only yourself” restriction, which is
imposed upon the set of all processes when some BSD-style
(without “-“) options are used or when the ps personality
setting is BSD-like.  The set of processes selected in this
manner is in addition to the set of processes selected by
other means.  An alternate description is that this option
causes ps to list all processes with a terminal (tty), or to
list all processes when used together with the x option.

-A     Select all processes.  Identical to -e.

-a     Select all processes except both session leaders (see
getsid(2)) and processes not associated with a terminal.

-d     Select all processes except session leaders.

–deselect
Select all processes except those that fulfill the specified
conditions (negates the selection).  Identical to -N.

-e     Select all processes.  Identical to -A.

g      Really all, even session leaders.  This flag is obsolete and
may be discontinued in a future release.  It is normally
implied by the a flag, and is only useful when operating in
the sunos4 personality.

-N     Select all processes except those that fulfill the specified
conditions (negates the selection).  Identical to –deselect.

T      Select all processes associated with this terminal.  Identical
to the t option without any argument.

r      Restrict the selection to only running processes.

x      Lift the BSD-style “must have a tty” restriction, which is
imposed upon the set of all processes when some BSD-style
(without “-“) options are used or when the ps personality
setting is BSD-like.  The set of processes selected in this
manner is in addition to the set of processes selected by
other means.  An alternate description is that this option
causes ps to list all processes owned by you (same EUID as
ps), or to list all processes when used together with the a
option.

PROCESS SELECTION BY LIST

These options accept a single argument in the form of a
blank-separated or comma-separated list.  They can be used multiple
times.  For example: ps -p “1 2” -p 3,4

-123   Identical to –pid 123.

123    Identical to –pid 123.

-C cmdlist
Select by command name.  This selects the processes whose
executable name is given in cmdlist.

-G grplist
Select by real group ID (RGID) or name.  This selects the
processes whose real group name or ID is in the grplist list.
The real group ID identifies the group of the user who created
the process, see getgid(2).

-g grplist
Select by session OR by effective group name.  Selection by
session is specified by many standards, but selection by
effective group is the logical behavior that several other
operating systems use.  This ps will select by session when
the list is completely numeric (as sessions are).  Group ID
numbers will work only when some group names are also
specified.  See the -s and –group options.

–Group grplist
Select by real group ID (RGID) or name.  Identical to -G.

–group grplist
Select by effective group ID (EGID) or name.  This selects the
processes whose effective group name or ID is in grplist.  The
effective group ID describes the group whose file access
permissions are used by the process (see getegid(2)).  The -g
option is often an alternative to –group.

p pidlist
Select by process ID.  Identical to -p and –pid.

-p pidlist
Select by PID.  This selects the processes whose process ID
numbers appear in pidlist.  Identical to p and –pid.

–pid pidlist
Select by process ID.  Identical to -p and p.

–ppid pidlist
Select by parent process ID.  This selects the processes with
a parent process ID in pidlist.  That is, it selects processes
that are children of those listed in pidlist.

q pidlist
Select by process ID (quick mode).  Identical to -q and
–quick-pid.

-q pidlist
Select by PID (quick mode).  This selects the processes whose
process ID numbers appear in pidlist.  With this option ps
reads the necessary info only for the pids listed in the
pidlist and doesn’t apply additional filtering rules. The
order of pids is unsorted and preserved. No additional
selection options, sorting and forest type listings are
allowed in this mode.  Identical to q and –quick-pid.

–quick-pid pidlist
Select by process ID (quick mode).  Identical to -q and q.

-s sesslist
Select by session ID.  This selects the processes with a
session ID specified in sesslist.

–sid sesslist
Select by session ID.  Identical to -s.

t ttylist
Select by tty.  Nearly identical to -t and –tty, but can also
be used with an empty ttylist to indicate the terminal
associated with ps.  Using the T option is considered cleaner
than using t with an empty ttylist.

-t ttylist
Select by tty.  This selects the processes associated with the
terminals given in ttylist.  Terminals (ttys, or screens for
text output) can be specified in several forms: /dev/ttyS1,
ttyS1, S1.  A plain “-” may be used to select processes not
attached to any terminal.

–tty ttylist
Select by terminal.  Identical to -t and t.

U userlist
Select by effective user ID (EUID) or name.  This selects the
processes whose effective user name or ID is in userlist.  The
effective user ID describes the user whose file access
permissions are used by the process (see geteuid(2)).
Identical to -u and –user.

-U userlist
Select by real user ID (RUID) or name.  It selects the
processes whose real user name or ID is in the userlist list.
The real user ID identifies the user who created the process,
see getuid(2).

-u userlist
Select by effective user ID (EUID) or name.  This selects the
processes whose effective user name or ID is in userlist.

The effective user ID describes the user whose file access
permissions are used by the process (see geteuid(2)).
Identical to U and –user.

–User userlist
Select by real user ID (RUID) or name.  Identical to -U.

–user userlist
Select by effective user ID (EUID) or name.  Identical to -u
and U.

OUTPUT FORMAT CONTROL

These options are used to choose the information displayed by ps.
The output may differ by personality.

-c     Show different scheduler information for the -l option.

–context
Display security context format (for SELinux).

-f     Do full-format listing. This option can be combined with many
other UNIX-style options to add additional columns.  It also
causes the command arguments to be printed.  When used with
-L, the NLWP (number of threads) and LWP (thread ID) columns
will be added.  See the c option, the format keyword args, and
the format keyword comm.

-F     Extra full format.  See the -f option, which -F implies.

–format format
user-defined format.  Identical to -o and o.

j      BSD job control format.

-j     Jobs format.

l      Display BSD long format.

-l     Long format.  The -y option is often useful with this.

-M     Add a column of security data.  Identical to Z (for SELinux).

O format
is preloaded o (overloaded).  The BSD O option can act like -O
(user-defined output format with some common fields
predefined) or can be used to specify sort order.  Heuristics
are used to determine the behavior of this option.  To ensure
that the desired behavior is obtained (sorting or formatting),
specify the option in some other way (e.g.  with -O or
–sort).  When used as a formatting option, it is identical to
-O, with the BSD personality.

-O format
Like -o, but preloaded with some default columns.  Identical
to -o pid,format,state,tname,time,command or -o pid,format,
tname,time,cmd, see -o below.

o format
Specify user-defined format.  Identical to -o and –format.

-o format
User-defined format.  format is a single argument in the form
of a blank-separated or comma-separated list, which offers a
way to specify individual output columns.  The recognized
keywords are described in the STANDARD FORMAT SPECIFIERS
section below.  Headers may be renamed (ps -o pid,
ruser=RealUser -o comm=Command) as desired.  If all column
headers are empty (ps -o pid= -o comm=) then the header line
will not be output.  Column width will increase as needed for
wide headers; this may be used to widen up columns such as
WCHAN (ps -o pid,wchan=WIDE-WCHAN-COLUMN -o comm).  Explicit
width control (ps opid,wchan:42,cmd) is offered too.  The
behavior of ps -o pid=X,comm=Y varies with personality; output
may be one column named “X,comm=Y” or two columns named “X”
and “Y”.  Use multiple -o options when in doubt.  Use the
PS_FORMAT environment variable to specify a default as
desired; DefSysV and DefBSD are macros that may be used to
choose the default UNIX or BSD columns.

s      Display signal format.

u      Display user-oriented format.

v      Display virtual memory format.

X      Register format.

-y     Do not show flags; show rss in place of addr.  This option can
only be used with -l.

Z      Add a column of security data.  Identical to -M (for SELinux).

OUTPUT MODIFIERS

c      Show the true command name.  This is derived from the name of
the executable file, rather than from the argv value.  Command
arguments and any modifications to them are thus not shown.
This option effectively turns the args format keyword into the
comm format keyword; it is useful with the -f format option
and with the various BSD-style format options, which all
normally display the command arguments.  See the -f option,
the format keyword args, and the format keyword comm.

–cols n
Set screen width.

–columns n
Set screen width.

–cumulative
Include some dead child process data (as a sum with the
parent).

e      Show the environment after the command.

f      ASCII art process hierarchy (forest).

–forest
ASCII art process tree.

h      No header.  (or, one header per screen in the BSD
personality).  The h option is problematic.  Standard BSD ps
uses this option to print a header on each page of output, but
older Linux ps uses this option to totally disable the header.
This version of ps follows the Linux usage of not printing the
header unless the BSD personality has been selected, in which
case it prints a header on each page of output.  Regardless of
the current personality, you can use the long options
–headers and –no-headers to enable printing headers each
page or disable headers entirely, respectively.

-H     Show process hierarchy (forest).

–headers
Repeat header lines, one per page of output.

k spec Specify sorting order.  Sorting syntax is
[+|-]key[,[+|-]key[,…]].  Choose a multi-letter key from the
STANDARD FORMAT SPECIFIERS section.  The “+” is optional since
default direction is increasing numerical or lexicographic
order.  Identical to –sort.

Examples:
ps jaxkuid,-ppid,+pid
ps axk comm o comm,args
ps kstart_time -ef

–lines n
Set screen height.

-n namelist
Set namelist file.  Identical to N.  The namelist file is
needed for a proper WCHAN display, and must match the current
Linux kernel exactly for correct output.  Without this option,
the default search path for the namelist is:

$PS_SYSMAP
$PS_SYSTEM_MAP
/proc/*/wchan
/boot/System.map-$(uname -r)
/boot/System.map
/lib/modules/$(uname -r)/System.map
/usr/src/linux/System.map
/System.map

n      Numeric output for WCHAN and USER (including all types of UID
and GID).

N namelist
Specify namelist file.  Identical to -n, see -n above.

–no-headers
Print no header line at all.  –no-heading is an alias for
this option.

O order
Sorting order (overloaded).  The BSD O option can act like -O
(user-defined output format with some common fields
predefined) or can be used to specify sort order.  Heuristics
are used to determine the behavior of this option.  To ensure
that the desired behavior is obtained (sorting or formatting),
specify the option in some other way (e.g.  with -O or
–sort).

For sorting, obsolete BSD O option syntax is
O[+|-]k1[,[+|-]k2[,…]].  It orders the processes listing
according to the multilevel sort specified by the sequence of
one-letter short keys k1,k2, …  described in the OBSOLETE
SORT KEYS section below.  The “+” is currently optional,
merely re-iterating the default direction on a key, but may
help to distinguish an O sort from an O format.  The “-”
reverses direction only on the key it precedes.

–rows n
Set screen height.

S      Sum up some information, such as CPU usage, from dead child
processes into their parent.  This is useful for examining a
system where a parent process repeatedly forks off short-lived
children to do work.

–sort spec
Specify sorting order.  Sorting syntax is
[+|-]key[,[+|-]key[,…]].  Choose a multi-letter key from the
STANDARD FORMAT SPECIFIERS section.  The “+” is optional since
default direction is increasing numerical or lexicographic
order.  Identical to k.  For example: ps jax –sort=uid,-ppid,
+pid

w      Wide output.  Use this option twice for unlimited width.

-w     Wide output.  Use this option twice for unlimited width.

–width n
Set screen width.

THREAD DISPLAY

H      Show threads as if they were processes.

-L     Show threads, possibly with LWP and NLWP columns.

m      Show threads after processes.

-m     Show threads after processes.

-T     Show threads, possibly with SPID column.

OTHER INFORMATION

–help section
Print a help message.  The section argument can be one of
simple, list, output, threads, misc or all.  The argument can
be shortened to one of the underlined letters as in:
s|l|o|t|m|a.

–info Print debugging info.

L      List all format specifiers.

V      Print the procps-ng version.

-V     Print the procps-ng version.

–version
Print the procps-ng version.

NOTES

This ps works by reading the virtual files in /proc.  This ps does
not need to be setuid kmem or have any privileges to run.  Do not
give this ps any special permissions.

This ps needs access to namelist data for proper WCHAN display.  For
kernels prior to 2.6, the System.map file must be installed.

CPU usage is currently expressed as the percentage of time spent
running during the entire lifetime of a process.  This is not ideal,
and it does not conform to the standards that ps otherwise conforms
to.  CPU usage is unlikely to add up to exactly 100%.

The SIZE and RSS fields don’t count some parts of a process including
the page tables, kernel stack, struct thread_info, and struct
task_struct.  This is usually at least 20 KiB of memory that is
always resident.  SIZE is the virtual size of the process (code+data+
stack).

Processes marked <defunct> are dead processes (so-called “zombies”)
that remain because their parent has not destroyed them properly.
These processes will be destroyed by init(8) if the parent process
exits.

If the length of the username is greater than the length of the
display column, the numeric user ID is displayed instead.

Commands options such as ps -aux are not recommended as it is a
confusion of two different standards.  According to the POSIX and
UNIX standards, the above command asks to display all processes with
a TTY (generally the commands users are running) plus all processes
owned by a user named “x”.  If that user doesn’t exist, then ps will
assume you really meant “ps aux”.

PROCESS FLAGS

The sum of these values is displayed in the “F” column, which is
provided by the flags output specifier:

1    forked but didn’t exec
4    used super-user privileges

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)
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

OBSOLETE SORT KEYS

These keys are used by the BSD O option (when it is used for
sorting).  The GNU –sort option doesn’t use these keys, but the
specifiers described below in the STANDARD FORMAT SPECIFIERS section.
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
(e.g.  sorting on tty will sort into device number, not according to
the terminal name displayed).  Pipe ps output into the sort(1)
command if you want to sort the cooked values.

KEY   LONG         DESCRIPTION
c     cmd          simple name of executable
C     pcpu         cpu utilization
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
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 device number of the controlling tty
T     start_time   time process was started
U     uid          user ID number
u     user         user name
v     vsize        total VM size in KiB
y     priority     kernel scheduling priority

AIX FORMAT DESCRIPTORS

This ps supports AIX format descriptors, which work somewhat like the
formatting codes of printf(1) and printf(3).  For example, the normal
default output can be produced with this: ps -eo “%p %y %x %c”.  The
NORMAL codes are described in the next section.

CODE   NORMAL   HEADER
%C     pcpu     %CPU
%G     group    GROUP
%P     ppid     PPID
%U     user     USER
%a     args     COMMAND
%c     comm     COMMAND
%g     rgroup   RGROUP
%n     nice     NI
%p     pid      PID
%r     pgid     PGID
%t     etime    ELAPSED
%u     ruser    RUSER
%x     time     TIME
%y     tty      TTY
%z     vsz      VSZ

STANDARD FORMAT SPECIFIERS

Here are the different keywords that may be used to control the
output format (e.g. with option -o) or to sort the selected processes
with the GNU-style –sort option.

For example: ps -eo pid,user,args –sort user

This version of ps tries to recognize most of the keywords used in
other implementations of ps.

The following user-defined format specifiers may contain spaces:
args, cmd, comm, command, fname, ucmd, ucomm,
lstart, bsdstart, start.

Some keywords may not be available for sorting.

CODE        HEADER    DESCRIPTION

%cpu        %CPU      cpu utilization of the process in “##.#”
format.  Currently, it is the CPU time used
divided by the time the process has been
running (cputime/realtime ratio), expressed as
a percentage.  It will not add up to 100%
unless you are lucky.  (alias pcpu).

%mem        %MEM      ratio of the process’s resident set size  to
the physical memory on the machine, expressed
as a percentage.  (alias pmem).

args        COMMAND   command with all its arguments as a string.
Modifications to the arguments may be shown.
The output in this column may contain spaces.
A process marked <defunct> is partly dead,
waiting to be fully destroyed by its parent.
Sometimes the process args will be unavailable;
when this happens, ps will instead print the
executable name in brackets.  (alias
cmd, command).  See also the comm format
keyword, the -f option, and the c option.
When specified last, this column will extend to
the edge of the display.  If ps can not
determine display width, as when output is
redirected (piped) into a file or another
command, the output width is undefined (it may
be 80, unlimited, determined by the TERM
variable, and so on).  The COLUMNS environment
variable or –cols option may be used to
exactly determine the width in this case.  The
w or -w option may be also be used to adjust
width.

blocked     BLOCKED   mask of the blocked signals, see signal(7).
According to the width of the field, a 32 or
64-bit mask in hexadecimal format is displayed.
(alias sig_block, sigmask).

bsdstart    START     time the command started.  If the process was
started less than 24 hours ago, the output
format is ” HH:MM”, else it is ” Mmm:SS” (where
Mmm is the three letters of the month).  See
also lstart, start, start_time, and stime.

bsdtime     TIME      accumulated cpu time, user + system.  The
display format is usually “MMM:SS”, but can be
shifted to the right if the process used more
than 999 minutes of cpu time.

c           C         processor utilization. Currently, this is the
integer value of the percent usage over the
lifetime of the process.  (see %cpu).

caught      CAUGHT    mask of the caught signals, see signal(7).
According to the width of the field, a 32 or 64
bits mask in hexadecimal format is displayed.
(alias sig_catch, sigcatch).

cgroup      CGROUP    display control groups to which the process
belongs.

class       CLS       scheduling class of the process.  (alias
policy, cls).  Field’s possible values are:

–   not reported
TS  SCHED_OTHER
FF  SCHED_FIFO
RR  SCHED_RR
B   SCHED_BATCH
ISO SCHED_ISO
IDL SCHED_IDLE
?   unknown value

cls         CLS       scheduling class of the process.  (alias
policy, cls).  Field’s possible values are:

–   not reported
TS  SCHED_OTHER
FF  SCHED_FIFO
RR  SCHED_RR
B   SCHED_BATCH
ISO SCHED_ISO
IDL SCHED_IDLE
?   unknown value

cmd         CMD       see args.  (alias args, command).

comm        COMMAND   command name (only the executable name).
Modifications to the command name will not be
shown.  A process marked <defunct> is partly
dead, waiting to be fully destroyed by its
parent.  The output in this column may contain
spaces.  (alias ucmd, ucomm).  See also the
args format keyword, the -f option, and the c
option.
When specified last, this column will extend to
the edge of the display.  If ps can not
determine display width, as when output is
redirected (piped) into a file or another
command, the output width is undefined (it may
be 80, unlimited, determined by the TERM
variable, and so on).  The COLUMNS environment
variable or –cols option may be used to
exactly determine the width in this case.  The
w or -w option may be also be used to adjust
width.

command     COMMAND   See args.  (alias args, command).

cp          CP        per-mill (tenths of a percent) CPU usage.  (see
%cpu).

cputime     TIME      cumulative CPU time, “[DD-]hh:mm:ss” format.
(alias time).

drs         DRS       data resident set size, the amount of physical
memory devoted to other than executable code.

egid        EGID      effective group ID number of the process as a
decimal integer.  (alias gid).

egroup      EGROUP    effective group ID of the process.  This will
be the textual group ID, if it can be obtained
and the field width permits, or a decimal
representation otherwise.  (alias group).

eip         EIP       instruction pointer.

esp         ESP       stack pointer.

etime       ELAPSED   elapsed time since the process was started, in
the form [[DD-]hh:]mm:ss.

etimes      ELAPSED   elapsed time since the process was started, in
seconds.

euid        EUID      effective user ID (alias uid).

euser       EUSER     effective user name.  This will be the textual
user ID, if it can be obtained and the field
width permits, or a decimal representation
otherwise.  The n option can be used to force
the decimal representation.  (alias
uname, user).

f           F         flags associated with the process, see the
PROCESS FLAGS section.  (alias flag, flags).

fgid        FGID      filesystem access group ID.  (alias fsgid).

fgroup      FGROUP    filesystem access group ID.  This will be the
textual group ID, if it can be obtained and the
field width permits, or a decimal
representation otherwise.  (alias fsgroup).

flag        F         see f.  (alias f, flags).

flags       F         see f.  (alias f, flag).

fname       COMMAND   first 8 bytes of the base name of the process’s
executable file.  The output in this column may
contain spaces.

fuid        FUID      filesystem access user ID.  (alias fsuid).

fuser       FUSER     filesystem access user ID.  This will be the
textual user ID, if it can be obtained and the
field width permits, or a decimal
representation otherwise.

gid         GID       see egid.  (alias egid).

group       GROUP     see egroup.  (alias egroup).

ignored     IGNORED   mask of the ignored signals, see signal(7).
According to the width of the field, a 32 or 64
bits mask in hexadecimal format is displayed.
(alias sig_ignore, sigignore).

ipcns       IPCNS     Unique inode number describing the namespace
the process belongs to. See namespaces(7).

label       LABEL     security label, most commonly used for SELinux
context data.  This is for the Mandatory Access
Control (“MAC”) found on high-security systems.

lstart      STARTED   time the command started.  See also
bsdstart, start, start_time, and stime.

lsession    SESSION   displays the login session identifier of a
process, if systemd support has been included.

lwp         LWP       light weight process (thread) ID of the
dispatchable entity (alias spid, tid).  See tid
for additional information.

machine     MACHINE   displays the machine name for processes
assigned to VM or container, if systemd support
has been included.

maj_flt     MAJFLT    The number of major page faults that have
occurred with this process.

min_flt     MINFLT    The number of minor page faults that have
occurred with this process.

mntns       MNTNS     Unique inode number describing the namespace
the process belongs to. See namespaces(7).

netns       NETNS     Unique inode number describing the namespace
the process belongs to. See namespaces(7).

ni          NI        nice value. This ranges from 19 (nicest) to -20
(not nice to others), see nice(1).  (alias
nice).

nice        NI        see ni.(alias ni).

nlwp        NLWP      number of lwps (threads) in the process.
(alias thcount).

nwchan      WCHAN     address of the kernel function where the
process is sleeping (use wchan if you want the
kernel function name).  Running tasks will
display a dash (‘-‘) in this column.

ouid        OWNER     displays the Unix user identifier of the owner
of the session of a process, if systemd support
has been included.

pcpu        %CPU      see %cpu.  (alias %cpu).

pending     PENDING   mask of the pending signals. See signal(7).
Signals pending on the process are distinct
from signals pending on individual threads.
Use the m option or the -m option to see both.
According to the width of the field, a 32 or 64
bits mask in hexadecimal format is displayed.
(alias sig).

pgid        PGID      process group ID or, equivalently, the process
ID of the process group leader.  (alias pgrp).

pgrp        PGRP      see pgid.  (alias pgid).

pid         PID       a number representing the process ID (alias
tgid).

pidns       PIDNS     Unique inode number describing the namespace
the process belongs to. See namespaces(7).

pmem        %MEM      see %mem.  (alias %mem).

policy      POL       scheduling class of the process.  (alias
class, cls).  Possible values are:

–   not reported
TS  SCHED_OTHER
FF  SCHED_FIFO
RR  SCHED_RR
B   SCHED_BATCH
ISO SCHED_ISO
IDL SCHED_IDLE
?   unknown value

ppid        PPID      parent process ID.

pri         PRI       priority of the process.  Higher number means
lower priority.

psr         PSR       processor that process is currently assigned
to.

rgid        RGID      real group ID.

rgroup      RGROUP    real group name.  This will be the textual
group ID, if it can be obtained and the field
width permits, or a decimal representation
otherwise.

rss         RSS       resident set size, the non-swapped physical
memory that a task has used (in kiloBytes).
(alias rssize, rsz).

rssize      RSS       see rss.  (alias rss, rsz).

rsz         RSZ       see rss.  (alias rss, rssize).

rtprio      RTPRIO    realtime priority.

ruid        RUID      real user ID.

ruser       RUSER     real user ID.  This will be the textual user
ID, if it can be obtained and the field width
permits, or a decimal representation otherwise.

s           S         minimal state display (one character).  See
section PROCESS STATE CODES for the different
values.  See also stat if you want additional
information displayed.  (alias state).

sched       SCH       scheduling policy of the process.  The policies
SCHED_OTHER (SCHED_NORMAL), SCHED_FIFO,
SCHED_RR, SCHED_BATCH, SCHED_ISO, and
SCHED_IDLE are respectively displayed as 0, 1,
2, 3, 4, and 5.

seat        SEAT      displays the identifier associated with all
hardware devices assigned to a specific
workplace, if systemd support has been
included.

sess        SESS      session ID or, equivalently, the process ID of
the session leader.  (alias session, sid).

sgi_p       P         processor that the process is currently
executing on.  Displays “*” if the process is
not currently running or runnable.

sgid        SGID      saved group ID.  (alias svgid).

sgroup      SGROUP    saved group name.  This will be the textual
group ID, if it can be obtained and the field
width permits, or a decimal representation
otherwise.

sid         SID       see sess.  (alias sess, session).

sig         PENDING   see pending.  (alias pending, sig_pend).

sigcatch    CAUGHT    see caught.  (alias caught, sig_catch).

sigignore   IGNORED   see ignored.  (alias ignored, sig_ignore).

sigmask     BLOCKED   see blocked.  (alias blocked, sig_block).

size        SIZE      approximate amount of swap space that would be
required if the process were to dirty all
writable pages and then be swapped out.  This
number is very rough!

slice       SLICE     displays the slice unit which a process belongs
to, if systemd support has been included.

spid        SPID      see lwp.  (alias lwp, tid).

stackp      STACKP    address of the bottom (start) of stack for the
process.

start       STARTED   time the command started.  If the process was
started less than 24 hours ago, the output
format is “HH:MM:SS”, else it is ”  Mmm dd”
(where Mmm is a three-letter month name).  See
also lstart, bsdstart, start_time, and stime.

start_time  START     starting time or date of the process.  Only the
year will be displayed if the process was not
started the same year ps was invoked, or
“MmmDD” if it was not started the same day, or
“HH:MM” otherwise.  See also
bsdstart, start, lstart, and stime.

stat        STAT      multi-character process state.  See section
PROCESS STATE CODES for the different values
meaning.  See also s and state if you just want
the first character displayed.

state       S         see s. (alias s).

suid        SUID      saved user ID.  (alias svuid).

supgid      SUPGID    group ids of supplementary groups, if any.  See
getgroups(2).

supgrp      SUPGRP    group names of supplementary groups, if any.
See getgroups(2).

suser       SUSER     saved user name.  This will be the textual user
ID, if it can be obtained and the field width
permits, or a decimal representation otherwise.
(alias svuser).

svgid       SVGID     see sgid.  (alias sgid).

svuid       SVUID     see suid.  (alias suid).

sz          SZ        size in physical pages of the core image of the
process.  This includes text, data, and stack
space.  Device mappings are currently excluded;
this is subject to change.  See vsz and rss.

tgid        TGID      a number representing the thread group to which
a task belongs (alias pid).  It is the process
ID of the thread group leader.

thcount     THCNT     see nlwp.  (alias nlwp).  number of kernel
threads owned by the process.

tid         TID       the unique number representing a dispatchable
entity (alias lwp, spid).  This value may also
appear as: a process ID (pid); a process group
ID (pgrp); a session ID for the session leader
(sid); a thread group ID for the thread group
leader (tgid); and a tty process group ID for
the process group leader (tpgid).

time        TIME      cumulative CPU time, “[DD-]HH:MM:SS” format.
(alias cputime).

tname       TTY       controlling tty (terminal).  (alias tt, tty).

tpgid       TPGID     ID of the foreground process group on the tty
(terminal) that the process is connected to, or
-1 if the process is not connected to a tty.

trs         TRS       text resident set size, the amount of physical
memory devoted to executable code.

tt          TT        controlling tty (terminal).  (alias
tname, tty).

tty         TT        controlling tty (terminal).  (alias tname, tt).

ucmd        CMD       see comm.  (alias comm, ucomm).

ucomm       COMMAND   see comm.  (alias comm, ucmd).

uid         UID       see euid.  (alias euid).

uname       USER      see euser.  (alias euser, user).

unit        UNIT      displays unit which a process belongs to, if
systemd support has been included.

user        USER      see euser.  (alias euser, uname).

userns      USERNS    Unique inode number describing the namespace
the process belongs to. See namespaces(7).

utsns       UTSNS     Unique inode number describing the namespace
the process belongs to. See namespaces(7).

uunit       UUNIT     displays user unit which a process belongs to,
if systemd support has been included.

vsize       VSZ       see vsz.  (alias vsz).

vsz         VSZ       virtual memory size of the process in KiB
(1024-byte units).  Device mappings are
currently excluded; this is subject to change.
(alias vsize).

wchan       WCHAN     name of the kernel function in which the
process is sleeping, a “-” if the process is
running, or a “*” if the process is
multi-threaded and ps is not displaying
threads.

ENVIRONMENT VARIABLES

The following environment variables could affect ps:

COLUMNS
Override default display width.

LINES
Override default display height.

PS_PERSONALITY
Set to one of posix, old, linux, bsd, sun, digital…  (see
section PERSONALITY below).

CMD_ENV
Set to one of posix, old, linux, bsd, sun, digital…  (see
section PERSONALITY below).

I_WANT_A_BROKEN_PS
Force obsolete command line interpretation.

LC_TIME
Date format.

PS_COLORS
Not currently supported.

PS_FORMAT
Default output format override. You may set this to a format
string of the type used for the -o option.  The DefSysV and DefBSD
values are particularly useful.

PS_SYSMAP
Default namelist (System.map) location.

PS_SYSTEM_MAP
Default namelist (System.map) location.

POSIXLY_CORRECT
Don’t find excuses to ignore bad “features”.

POSIX2
When set to “on”, acts as POSIXLY_CORRECT.

UNIX95
Don’t find excuses to ignore bad “features”.

_XPG
Cancel CMD_ENV=irix non-standard behavior.

In general, it is a bad idea to set these variables.  The one
exception is CMD_ENV or PS_PERSONALITY, which could be set to Linux
for normal systems.  Without that setting, ps follows the useless and
bad parts of the Unix98 standard.

PERSONALITY

390        like the OS/390 OpenEdition ps

aix        like AIX ps
bsd        like FreeBSD ps (totally non-standard)
compaq     like Digital Unix ps
debian     like the old Debian ps
digital    like Tru64 (was Digital Unix, was OSF/1) ps
gnu        like the old Debian ps
hp         like HP-UX ps
hpux       like HP-UX ps
irix       like Irix ps
linux      ***** recommended *****
old        like the original Linux ps (totally non-standard)
os390      like OS/390 Open Edition ps
posix      standard
s390       like OS/390 Open Edition ps
sco        like SCO ps
sgi        like Irix ps
solaris2   like Solaris 2+ (SunOS 5) ps
sunos4     like SunOS 4 (Solaris 1) ps (totally non-standard)
svr4       standard
sysv       standard
tru64      like Tru64 (was Digital Unix, was OSF/1) ps
unix       standard
unix95     standard
unix98     standard

SEE ALSO

pgrep(1), pstree(1), top(1), proc(5).

STANDARDS

This ps conforms to:

1   Version 2 of the Single Unix Specification
2   The Open Group Technical Standard Base Specifications, Issue 6
3   IEEE Std 1003.1, 2004 Edition
4   X/Open System Interfaces Extension [UP XSI]
5   ISO/IEC 9945:2003

AUTHOR

ps was originally written by Branko Lankester ⟨[email protected]⟩.
Michael K. Johnson ⟨[email protected]⟩ re-wrote it significantly to
use the proc filesystem, changing a few things in the process.
Michael Shields ⟨[email protected]⟩ added the pid-list feature.
Charles Blake ⟨[email protected]⟩ 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.  Albert Cahalan ⟨[email protected]⟩ rewrote
ps for full Unix98 and BSD support, along with some ugly hacks for
obsolete and foreign syntax.

Please send bug reports to ⟨[email protected]⟩.  No subscription
is required or suggested.

COLOPHON

This page is part of the procps-ng (/proc filesystem utilities)
project.  Information about the project can be found at
⟨http://sourceforge.net/projects/procps-ng/⟩.  If you have a bug
report for this manual page, see
⟨http://sourceforge.net/p/procps-ng/tickets/⟩.  This page was obtained
from the project’s upstream Git repository
(https://gitorious.org/procps) on 2014-12-30.  If you discover any
rendering problems in this HTML version of the page, or you believe
there is a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
[email protected]

procps-ng                         July 2014                            PS(1)

Author:

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