Manual Pages  — PS

ps – process status

SYNOPSIS DESCRIPTION KEYWORDS ENVIRONMENT FILES EXIT STATUS EXAMPLES SEE ALSO STANDARDS HISTORY BUGS

ps [--libxo] [-AaCcdefHhjlmrSTuvwXxZ] [-O fmt] [-o fmt] [-D up | down | both] [-G gid[,gid...]] [-J jid[,jid...]] [-M core] [-N system] [-p pid[,pid...]] [-t tty[,tty...]] [-U user[,user...]]
ps [--libxo] -L

The ps utility displays information about a selection of processes. Its traditional text style output consists of a header line followed by one line of information per selected process, or possibly multiple ones if using -H (one per lightweight-process). Other output styles can be requested via --libxo.

By default, only the processes of the calling user, determined by matching their effective user ID with that of the ps process, that have controlling terminals are shown. A different set of processes can be selected for display by using combinations of the -A -, -a -, -D -, -G -, -J -, -p -, -T -, -t -, -U -, -X, and -x options. Except for options -X and -x, as soon as one of them appears, it inhibits the default process selection, i.e., the calling user's processes are shown only on request. If more than one of these (with same exceptions) appear, ps will select processes as soon as they are matched by at least one of them (inclusive OR). The -X option can be independently used to further filter the listed processes to only those that have a controlling terminal ( except for those selected by -p ). Its opposite, -x, forcefully removes that filter. If none of -X and -x is specified, the implied default behavior is that of -X unless using another option whose description explicitly says that -x is implied.

For each selected process, the default displayed information consists of the process' ID, controlling terminal, state, CPU time (including both user and system time) and associated command ( see the documentation for the command keyword below ). This information can be tweaked using two groups of options which can be combined as needed. First, options -o and -O add columns with data corresponding to the explicitly passed keywords. Available keywords are documented in the KEYWORDS section below. They can be listed using option -L. Second, options -j -, -l -, -u, and -v designate specific predefined groups of columns, also called canned displays. Appearance of any of these options inhibits the default display, replacing it all with the requested columns, and in the order options are passed. The individual columns requested via a canned display option that have the same keyword or an alias to that of some column added by an earlier canned display option, or by an explicit -O or -o option anywhere on the command line, are suppressed. This automatic removal of duplicate data in canned displays is useful for slightly tweaking these displays and/or combining multiple ones without having to rebuild variants from scratch, e.g., using only -o options.

Output information lines are by default sorted first by controlling terminal, then by process ID, and then, if -H has been specified, by lightweight-process (thread) ID. The -m -, -r -, -u, and -v options will change the sort order. If more than one sorting option was given, then the selected processes will be sorted by the last sorting option which was specified.

If the traditional text output (the default) is used, the default output width is that requested by the COLUMNS environment variable if present, else the line width of the terminal associated to the ps process, if any. In all other situations, the output width is unlimited. See also the -w option and the BUGS section.

For backwards compatibility, ps attempts to interpret any positional argument as a process ID, as if specified by the -p option. Failure to do so will trigger an error. ps also accepts the old-style BSD options, whose format and effect are left undocumented on purpose.

The options are as follows:

--libxo
	Generate output via libxo(3) in a selection of different human and machine readable formats. See xo_parse_args(3) for details on command line arguments. The default is the traditional text style output.
-A
	Display information about all processes in the system. Using this option is strictly equivalent to specifying both -a and -x. Please see their description for more information.
-a
	Display information about all users' processes. It does not, however, list all processes ( see -A and -x ). If the security.bsd.see_other_uids sysctl is set to zero, this option is honored only if the real user ID of the ps process is 0.
-C
	Change the way the CPU percentage is calculated by using a "raw" CPU calculation that ignores "resident" time (this normally has no effect).
-c
	Change the "command" column output to just contain the executable name, rather than the full command line.
-D
	Expand the list of selected processes based on the process tree. "UP" will add the ancestor processes, "DOWN" will add the descendant processes, and "BOTH" will add both the ancestor and the descendant processes. -D does not imply -d, but works well with it.
-d
	Arrange processes into descendancy order and prefix each command with indentation text showing sibling and parent/child relationships as a tree. If either of the -m and -r options are also used, they control how sibling processes are sorted relative to each other. Note that this option has no effect if the last column does not have comm, command or ucomm as its keyword.
-e
	Display the environment as well.
-f
	Show command-line and environment information also for swapped out processes. This option is honored only if the UID of the user is 0.
-G
	Display information about processes whose real group ID matches the specified group IDs or names. Implies -x by default.
-H
	Show all of the threads associated with each process.
-h
	Repeat the information header as often as necessary to guarantee one header per page of information.
-J
	Display information about processes which match the specified jail IDs. This may be either the jid or name of the jail. Use -J 0 to request display of host processes. Implies -x by default.
-j
	Print information associated with the following keywords: user, pid, ppid, pgid, sid, jobc, state, tt, time, and command.
-L
	List the set of keywords available for the -O and -o options.
-l
	Display information associated with the following keywords: uid, pid, ppid, cpu, pri, nice, vsz, rss, mwchan, state, tt, time, and command.
-M
	Extract values associated with the name list from the specified core instead of the currently running system.
-m
	Sort by memory usage, instead of the combination of controlling terminal and process ID.
-N
	Extract the name list from the specified system instead of the default, which is the kernel image the system has booted from.
-O
	Save passed columns in a separate list that in the end is grafted just after the display's first occurence of the process ID column as specified by other options, or the default display if there is none. If the display prepared by other options does not include a process ID column, the list is inserted at start of the display. Further occurences of -O append to the to-be-grafted list of columns. This option takes a space- or comma-separated list of keywords. The last keyword in the list may be appended with an equals sign (‘=’) as explained for option -o and with the same effect.
-o
	Display information associated with the space- or comma-separated list of keywords specified. The last keyword in the list may be appended with an equals sign (‘=’) and a string that spans the rest of the argument, and can contain space and comma characters. This causes the printed header to use the specified string instead of the standard header. Multiple keywords may also be given in the form of more than one -o option. So the header texts for multiple keywords can be changed. If all keywords have empty header texts, no header line is written.
-p
	Display information about processes which match the specified process IDs. Processes selected by this option are not subject to being filtered by -X.
-r
	Sort by current CPU usage, instead of the combination of controlling terminal and process ID.
-S
	Change the way the process times, namely cputime, systime, and usertime, are calculated by summing all exited children to their parent process.
-T
	Display information about processes attached to the device associated with the standard input.
-t
	Display information about processes attached to the specified terminal devices. Full pathnames, as well as abbreviations (see explanation of the tt keyword) can be specified. Implies -x by default.
-U
	Display information about processes whose real user ID matches the specified user IDs or names. Implies -x by default.
-u
	Display information associated with the following keywords: user, pid, %cpu, %mem, vsz, rss, tt, state, start, time, and command. The -u option implies the -r option.
-v
	Display information associated with the following keywords: pid, state, time, sl, re, pagein, vsz, rss, lim, tsiz, %cpu, %mem, and command. The -v option implies the -m option.
-w
	Use at least 131 columns to display information. If -w is specified more than once, ps will use as many columns as necessary. Please see the preamble of this manual page for how the output width is initially determined. In particular, if the initial output width is unlimited, specifying -w has no effect. Please also consult the BUGS section.
-X
	When displaying processes selected by other options, skip any processes which do not have a controlling terminal, except for those selected through -p. This is the default behaviour, unless using another option whose description explicitly says that -x is implied.
-x
	When displaying processes selected by other options, include processes which do not have a controlling terminal. This option has the opposite behavior to that of -X. If both -X and -x are specified, ps will obey the last occurence.
-Z
	Add mac(4) label to the list of keywords for which ps will display information.

The following is a complete list of the available keywords and their meanings. Several of them have aliases (keywords which are synonyms). Detailed descriptions for some of them can be found after this list.

%cpu	percentage CPU usage (alias pcpu)
%mem	percentage memory usage (alias pmem)
acflag	accounting flag (alias acflg)
args	command and arguments
class	login class
comm	command
command	command and arguments
cow	number of copy-on-write faults
cpu	The processor number on which the process is executing (visible only on SMP systems).
dsiz	data size in KiB
emul	system-call emulation environment (ABI)
etime	elapsed running time, format " [days-] [hoursamp;:] minutes:seconds "
etimes	elapsed running time, in decimal integer seconds
fib	default FIB number, see setfib(1)
flags	the process flags, in hexadecimal (alias f)
flags2	the additional set of process flags, in hexadecimal (alias f2)
gid	effective group ID (alias egid)
group	group name (from egid) (alias egroup)
inblk	total blocks read (alias inblock)
jail	jail name
jid	jail ID
jobc	job control count
ktrace	tracing flags
label	MAC label
lim	memoryuse limit
lockname	lock currently blocked on (as a symbolic name)
logname	login name of user who started the session
lstart	time started
lwp	thread (light-weight process) ID (alias tid)
majflt	total page faults
minflt	total page reclaims
msgrcv	total messages received (reads from pipes/sockets)
msgsnd	total messages sent (writes on pipes/sockets)
mwchan	wait channel or lock currently blocked on
nice	nice value (alias ni)
nivcsw	total involuntary context switches
nlwp	number of threads (light-weight processes) tied to a process
nsigs	total signals taken (alias nsignals)
nswap	total swaps in/out
nvcsw	total voluntary context switches
nwchan	wait channel (as an address)
oublk	total blocks written (alias oublock)
paddr	process pointer
pagein	pageins (same as majflt)
pgid	process group number
pid	process ID
ppid	parent process ID
pri	scheduling priority
re	core residency time (in seconds; 127 = infinity)
rgid	real group ID
rgroup	group name (from rgid)
rss	resident set size in KiB
rtprio	realtime priority (see rtprio(1))
ruid	real user ID
ruser	user name (from ruid)
sid	session ID
sig	pending signals (alias pending)
sigcatch	caught signals (alias caught)
sigignore
	ignored signals (alias ignored)
sigmask	blocked signals (alias blocked)
sl	sleep time (in seconds; 127 = infinity)
ssiz	stack size in KiB
start	time started
state	symbolic process state (alias stat)
svgid	saved gid from a setgid executable
svuid	saved UID from a setuid executable
systime	accumulated system CPU time
tdaddr	thread address
tdname	thread name
tdev	control terminal device number
time	accumulated CPU time, user + system (alias cputime)
tpgid	control terminal process group ID
tracer	tracer process ID
tsid	control terminal session ID
tsiz	text size in KiB
tt	control terminal name (two letter abbreviation)
tty	full name of control terminal
ucomm	process name used for accounting
uid	effective user ID (alias euid)
upr	scheduling priority on return from system call (alias usrpri)
uprocp	process pointer
user	user name (from UID)
usertime	accumulated user CPU time
vmaddr	vmspace pointer
vsz	virtual size in KiB (alias vsize)
wchan	wait channel (as a symbolic name)
xstat	exit or stop status (valid only for stopped or zombie process)

Some of these keywords are further specified as follows:

%cpu	The CPU utilization of the process; this is a decaying average over up to a minute of previous (real) time. Since the time base over which this is computed varies (since processes may be very young) it is possible for the sum of all %cpu fields to exceed 100%.
%mem	The percentage of real memory used by this process.
class	Login class associated with the process.
command	The printed command and arguments are determined as follows. A process that has exited and has a parent that has not yet waited for the process (in other words, a zombie) is listed as "<defunct>." If the arguments cannot be located ( usually because they have not been set, as is the case for system processes and/or kernel threads ), the command name is printed within square brackets. The ps utility first tries to obtain the arguments cached by the kernel ( if they were shorter than the value of the kern.ps_arg_cache_limit sysctl ). The process can change the arguments shown with setproctitle(3). Otherwise, ps makes an educated guess as to the file name and arguments given when the process was created by examining memory or the swap area. The method is inherently somewhat unreliable and in any event a process is entitled to destroy this information. The ucomm keyword (accounting) can, however, be depended on. If the arguments are unavailable or do not agree with the ucomm keyword, the value for the ucomm keyword is appended to the arguments in parentheses.
flags	The flags associated with the process as in the include file <sys/proc.h>: P_ADVLOCK 0x00000001 Process may hold a POSIX advisory lock P_CONTROLT 0x00000002 Has a controlling terminal P_KPROC 0x00000004 Kernel process P_PPWAIT 0x00000010 Parent is waiting for child to exec/exit P_PROFIL 0x00000020 Has started profiling P_STOPPROF 0x00000040 Has thread in requesting to stop prof P_HADTHREADS 0x00000080 Has had threads (no cleanup shortcuts) P_SUGID 0x00000100 Had set id privileges since last exec P_SYSTEM 0x00000200 System proc: no sigs, stats or swapping P_SINGLE_EXIT 0x00000400 Threads suspending should exit, not wait P_TRACED 0x00000800 Debugged process being traced P_WAITED 0x00001000 Someone is waiting for us P_WEXIT 0x00002000 Working on exiting P_EXEC 0x00004000 Process called exec P_WKILLED 0x00008000 Killed, shall go to kernel/user boundary ASAP P_CONTINUED 0x00010000 Proc has continued from a stopped state P_STOPPED_SIG 0x00020000 Stopped due to SIGSTOP/SIGTSTP P_STOPPED_TRACE 0x00040000 Stopped because of tracing P_STOPPED_SINGLE 0x00080000 Only one thread can continue P_PROTECTED 0x00100000 Do not kill on memory overcommit P_SIGEVENT 0x00200000 Process pending signals changed P_SINGLE_BOUNDARY 0x00400000 Threads should suspend at user boundary P_HWPMC 0x00800000 Process is using HWPMCs P_JAILED 0x01000000 Process is in jail P_TOTAL_STOP 0x02000000 Stopped for system suspend P_INEXEC 0x04000000 Process is inexecve(2) P_STATCHILD 0x08000000 Child process stopped or exited P_INMEM 0x10000000 Loaded into memory P_SWAPPINGOUT 0x20000000 Process is being swapped out P_SWAPPINGIN 0x40000000 Process is being swapped in P_PPTRACE 0x80000000 Vforked child issued ptrace(PT_TRACEME)
flags2	The flags kept in p_flag2 associated with the process as in the include file <sys/proc.h>: P2_INHERIT_PROTECTED 0x00000001 New children get P_PROTECTED P2_NOTRACE 0x00000002 ptrace(2) attach or coredumps P2_NOTRACE_EXEC 0x00000004 Keep P2_NOPTRACE onexecve(2) P2_AST_SU 0x00000008 Handles SU ast for kthreads P2_PTRACE_FSTP 0x00000010 SIGSTOP from PT_ATTACH not yet handled P2_TRAPCAP 0x00000020 SIGTRAP on ENOTCAPABLE P2_ASLR_ENABLE 0x00000040 Force enable ASLR P2_ASLR_DISABLE 0x00000080 Force disable ASLR P2_ASLR_IGNSTART 0x00000100 Enable ASLR to consume sbrk area P2_PROTMAX_ENABLE 0x00000200 Force enable implied PROT_MAX P2_PROTMAX_DISABLE 0x00000400 Force disable implied PROT_MAX P2_STKGAP_DISABLE 0x00000800 Disable stack gap for MAP_STACK P2_STKGAP_DISABLE_EXEC 0x00001000 Stack gap disabled after exec P2_ITSTOPPED 0x00002000 itimers stopped (as part of process stop) P2_PTRACEREQ 0x00004000 Active ptrace req P2_NO_NEW_PRIVS 0x00008000 Ignore setuid on exec P2_WXORX_DISABLE 0x00010000 WX mappings enabled P2_WXORX_ENABLE_EXEC 0x00020000 WxorX enabled after exec P2_WEXIT 0x00040000 Internal exit early state P2_REAPKILLED 0x00080000 REAP_KILL pass handled the process P2_MEMBAR_PRIVE 0x00100000 membarrier private expedited registered P2_MEMBAR_PRIVE_SYNCORE 0x00200000 membarrier private expedited sync core registered P2_MEMBAR_GLOBE 0x00400000 membar global expedited registered
label	The MAC label of the process.
lim	The soft limit on memory used, specified via a call to setrlimit(2).
lstart	The exact time the command started, using the ‘%c’ format described in strftime(3).
lockname
	The name of the lock that the process is currently blocked on. If the name is invalid or unknown, then "???amp;" is displayed.
logname	The login name associated with the session the process is in (see getlogin(2)).
mwchan	The event name if the process is blocked normally, or the lock name if the process is blocked on a lock. See the wchan and lockname keywords for details.
nice	The process scheduling increment (see setpriority(2)).
rss	the real memory (resident set) size of the process in KiB.
start	The time the command started. If the command started less than 24 hours ago, the start time is displayed using the "%H:%M" format described in strftime(3). If the command started less than 7 days ago, the start time is displayed using the "%a%H" format. Otherwise, the start time is displayed using the "%e%b%y" format.
sig	The bitmask of signals pending in the process queue if the -H option has not been specified, else the per-thread queue of pending signals.
state	The state is given by a sequence of characters, for example, "RWNA". The first character indicates the run state of the process:

D	Marks a process in disk (or other short term, uninterruptible) wait.
I	Marks a process that is idle (sleeping for longer than about 20 seconds).
L	Marks a process that is waiting to acquire a lock.
R	Marks a runnable process.
S	Marks a process that is sleeping for less than about 20 seconds.
T	Marks a stopped process.
W	Marks an idle interrupt thread.
Z	Marks a dead process (a "zombie").

Additional characters after these, if any, indicate additional state information:

+	The process is in the foreground process group of its control terminal.
<	The process has raised CPU scheduling priority.
C	The process is in capsicum(4) capability mode.
E	The process is trying to exit.
J	Marks a process which is in jail(2). The hostname of the prison can be found in /proc/<pid > /status.
L	The process has pages locked in core (for example, for raw I/O).
N	The process has reduced CPU scheduling priority (see setpriority(2)).
s	The process is a session leader.
V	The process' parent is suspended during a vfork(2), waiting for the process to exec or exit.
W	The process is swapped out.
X	The process is being traced or debugged.

tt	An abbreviation for the pathname of the controlling terminal, if any. The abbreviation consists of the three letters following /dev/tty, or, for pseudo-terminals, the corresponding entry in /dev/pts. This is followed by a ‘-’ if the process can no longer reach that controlling terminal (i.e., it has been revoked). A ‘-’ without a preceding two letter abbreviation or pseudo-terminal device number indicates a process which never had a controlling terminal. The full pathname of the controlling terminal is available via the tty keyword.
wchan	The event (an address in the system) on which a process waits. When printed numerically, the initial part of the address is trimmed off and the result is printed in hex, for example, 0x80324000 prints as 324000.

The following environment variables affect the execution of ps:

COLUMNS
	If set, specifies the user's preferred output width in column positions. Only affects the traditional text style output. Please see the preamble of this manual page on how the final output width is determined.

/boot/kernel/kernel
	default system namelist

The utility exits 0 on success, and >0 if an error occurs.

Display information on all system processes:

    $ ps -auxw

For historical reasons, the ps utility under FreeBSD supports a different set of options from what is described by IEEE Std 1003.1-2024 ("POSIX.1") and what is supported on non-Bx operating systems.

In particular, and contrary to this implementation, POSIX specifies that option -d should serve to select all processes except session leaders, option -e to select all processes ( equivalently to -A ), and option -u to select processes by effective user ID.

However, options -A -, -a -, -G -, -l -, -o -, -p -, -U, and -t behave as prescribed by IEEE Std 1003.1-2024 ("POSIX.1"). Options -f and -w currently do not, but may be changed to in the future.

POSIX's option -g, to select processes having the specified processes as their session leader, is not implemented. However, other UNIX systems that provide this functionality do so via option -s instead, reserving -g to query by group leaders.

The ps command appeared in AT&T v3 in section 8 of the manual.

Since ps cannot run faster than the system and is run as any other scheduled process, the information it displays can never be exact.

ps currently does not correctly limit the ouput width, and in most cases does not limit it at all when it should. Regardless of the target width, requested columns are always all printed and with widths allowing to entirely print their longest values, except for columns with keyword command or args that are not last in the display (they are truncated to 16 bytes), and for the last column in the display if its keyword requests textual information of variable length, such as the command, jail, and user keywords do. This considerably limits the effects and usefulness of the terminal width on the output, and consequently that of the COLUMNS environment variable and the -w option (if specified only once).

The ps utility does not correctly display argument lists containing multibyte characters.