ps Man page

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 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)
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.

-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). 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). 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.

-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). 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 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 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 and printf. 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 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 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. (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.

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

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, pstree, top, 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 ⟨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. Albert Cahalan ⟨albert@users.sf.net⟩ rewrote ps for full
Unix98 and BSD support, along with some ugly hacks for obsolete and
foreign syntax.

Please send bug reports to ⟨procps@freelists.org⟩. No subscription is
required or suggested.

procps-ng July 2014 PS(1)