ps

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:

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

Options of different types may be freely mixed, but conflicts can appear. There are some synonomous 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 -a. 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) as the curent user and associated with the same terminal as the invoker. It displays the process ID (PID), the terminal associated with the process (TTY), the cumulated CPU time in [dd-]hh:mm:ss format (TIME), and the executable name (CMD). Output is unsorted by default.

The use of BSD-style options will add process state (STAT) to the default display and show the command 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 (TTY) 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 -eo spid,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 -p 42 -o comm=

SIMPLE PROCESS SELECTION

-A: Select all processes. Identical to -e.
-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.
-a: Select all processes except session leaders (see getsid(2)) and processes not associated with a terminal.
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.
-d: Select all processes except session leaders.
-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.
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.
--deselect: Select all processes except those that fulfill the specified conditions. (negates the selection) Identical to -N.

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

-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).
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 getgid(2)). Identical to -u and --user.
-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.
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.
-s sesslist: Select by session ID. This selects the processes with a session ID specified in sesslist.
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.
-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.
--Group grplist: Select by real group ID (RGID) or name. Identical to -G.
--User userlist: Select by real user ID (RUID) or name. Identical to -U.
--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.
--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.
--sid sesslist: Select by session ID. Identical to -s.
--tty ttylist: Select by terminal. Identical to -t and t.
--user userlist: Select by effective user ID (EUID) or name. Identical to -u and U.
-pid: Identical to --sid pid.
pid: Identical to --pid pid.

OUTPUT FORMAT CONTROL

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

-F

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

-O format

is like -o, but preloaded with some default columns. Identical to

    ps -o pid,format,state,tname,time,command

    ps -o pid,format,tname,time,cmd

(see -o below).

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.

-M

Add a column of security data. Identical to Z (for SE Linux).

X

Z

Add a column of security data. Identical to -M (for SE Linux).

-c

Show different scheduler information for the -l option.

-f

does 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.

j

BSD job control format.

-j

jobs format

l

display BSD long format.

-l

long format. The -y option is often useful with this.

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,rusers=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 -o pid,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

--format format

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

--context

Display security context format (for SE Linux).

OUTPUT MODIFIERS

-H

show process hierarchy (forest)

N namelist

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

O format

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.

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.

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 (see setproctitle(3)) 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.

e

Show the environment after the command.

f

ASCII-art process hierarchy (forest).

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.

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

-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)

-w

Wide output. Use this option twice for unlimited width.

w

Wide output. Use this option twice for unlimited width.

--cols n

set screen width

--columns n

set screen width

--cumulative

include some dead child process data (as a sum with the parent)

--forest

ASCII art process tree

--headers

repeat header lines, one per page of output

--no-headers

print no header line at all

--lines n

set screen height

--rows n

set screen height

--sort spec

Identical to k. For example:

    ps jax --sort=uid,-ppid,+pid

--width n: set screen width

THREAD DISPLAY

H: Show threads as if they were processes.
-L: Show threads, possibly with LWP and NLWP columns.
-T: Show threads, possibly with SPID column.
m: Show threads after processes.

OTHER INFORMATION

L: List all format specifiers.
-V: Print the procps version.
V: Print the procps version.
--help: Print a help message.
--info: Print debugging info.
--version: Print the procps 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.

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)
D: Interruptible sleep (waiting for an event to complete)
T: Stopped, either by a job control signal or because it is being traced.
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 controling tty
T	start_time	time process was started
U	uid	user ID number
u	user	user name
v	vsize	total VM size in kB
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-bit 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 dd" (where mmm is the three letters of the month).
`bsdtime`	TIME	accumulated cpu time, user + system. The display format is usualy "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`).
`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 ? 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 ? 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`, `ucom`). 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`, `cmd`).
`cp`	CP	per-mill (tenths of a percent) CPU usage (see `%cpu`).
`cputime`	TIME	cumulative CPU time, "[dd-]hh:mm:ss" format. (alias `time`).
`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.
`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 user 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-bit or 64-bit mask in hexadecimal format is displayed. (alias `sig_ignore`, `sigignore`)
`label`	LABEL	security label, most commonly used for SE Linux context data. This is for the Mandatory Access Control ("MAC") found on high-security systems.
`lstart`	STARTED	time the command started.
`lwp`	LWP	lwp (light weight process, or thread) ID of the lwp being reported. (alias `spid`, `tid`) .
`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.
`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-bit or 64-bit 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	process ID number of the process.
`pmem`	%MEM	see `%mem`. (alias `%mem`).
`policy`	POL	scheduling class of the process. (alias `class`, `cls`). Field's possible values are: - not reported TS SCHED_OTHER FF SCHED_FIFO RR SCHED_RR ? unknown value
`ppid`	PPID	parent process ID.
`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 additionnal information displayed. (alias `state`).
`sched`	SCH	scheduling policy of the process. The policies sched_other, sched_fifo, and sched_rr are respectively displayed as 0, 1, and 2.
`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`	SZ	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!
`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).
`stat`	STAT	multi-character process state. See [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`).
`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`.
`thcount`	THCNT	number of kernel threads owned by the process. see `nlwp`. (alias `nlwp`).
`tid`	TID	see `lwp`. (alias `lwp`).
`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.
`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`).
`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 S/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

STANDARDS

This ps conforms to:

Version 2 of the Single Unix Specification
The Open Group Technical Standard Base Specifications, Issue 6
IEEE Std 1003.1, 2004 Edition
X/Open System Interfaces Extension [UP XSI]
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-feedback@lists.sf.net>. No subscription is required or suggested.