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PS(1) General Commands Manual PS(1)

ps — process status

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:

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.
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.
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.
Change the way the CPU percentage is calculated by using a “raw” CPU calculation that ignores “resident” time (this normally has no effect).
Change the “command” column output to just contain the executable name, rather than the full command line.
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.
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.
Display the environment as well.
Indicates to print the full command and arguments in command columns. This is the default behavior on FreeBSD. See -c to turn it off.
Display information about processes whose real group ID matches the specified group IDs or names. Implies -x by default.
Show all of the threads associated with each process.
Repeat the information header as often as necessary to guarantee one header per page of information.
Display information about processes which match the specified jail IDs. This may be either the jid or name of the jail. Use -J to display only host processes. Implies -x by default.
Print information associated with the following keywords: user, pid, ppid, pgid, sid, jobc, state, tt, time, and command.
List the set of keywords available for the -O and -o options.
Display information associated with the following keywords: uid, pid, ppid, cpu, pri, nice, vsz, rss, mwchan, state, tt, time, and command.
Extract values associated with the name list from the specified core instead of the currently running system.
Sort by memory usage, instead of the combination of controlling terminal and process ID.
Extract the name list from the specified system instead of the default, which is the kernel image the system has booted from.
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.
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.
Display information about processes which match the specified process IDs. Processes selected by this option are not subject to being filtered by -X.
Sort by current CPU usage, instead of the combination of controlling terminal and process ID.
Change the way the process times, namely cputime, systime, and usertime, are calculated by summing all exited children to their parent process.
Display information about processes attached to the device associated with the standard input.
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.
Display information about processes whose real user ID matches the specified user IDs or names. Implies -x by default.
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.
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.
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.
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.
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.
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.

percentage CPU usage (alias pcpu)
percentage memory usage (alias pmem)
accounting flag (alias acflg)
command and arguments
login class
command
command and arguments
number of copy-on-write faults
The processor number on which the process is executing (visible only on SMP systems).
data size in KiB
system-call emulation environment (ABI)
elapsed running time, format “[days-][hours:]minutes:seconds”
elapsed running time, in decimal integer seconds
default FIB number, see setfib(1)
the process flags, in hexadecimal (alias f)
the additional set of process flags, in hexadecimal (alias f2)
effective group ID (alias egid)
group name (from egid) (alias egroup)
total blocks read (alias inblock)
jail name
jail ID
job control count
tracing flags
MAC label
memoryuse limit
lock currently blocked on (as a symbolic name)
login name of user who started the session
time started
thread (light-weight process) ID (alias tid)
total page faults
total page reclaims
total messages received (reads from pipes/sockets)
total messages sent (writes on pipes/sockets)
wait channel or lock currently blocked on
nice value (alias ni)
total involuntary context switches
number of threads (light-weight processes) tied to a process
total signals taken (alias nsignals)
total swaps in/out
total voluntary context switches
wait channel (as an address)
total blocks written (alias oublock)
process pointer
pageins (same as majflt)
process group number
process ID
parent process ID
scheduling priority
core residency time (in seconds; 127 = infinity)
real group ID
group name (from rgid)
resident set size in KiB
realtime priority (see rtprio(1))
real user ID
user name (from ruid)
session ID
pending signals (alias pending)
caught signals (alias caught)
ignored signals (alias ignored)
blocked signals (alias blocked)
sleep time (in seconds; 127 = infinity)
stack size in KiB
time started
symbolic process state (alias stat)
saved gid from a setgid executable
saved UID from a setuid executable
accumulated system CPU time
thread address
thread name
control terminal device number
accumulated CPU time, user + system (alias cputime)
control terminal process group ID
tracer process ID
control terminal session ID
text size in KiB
control terminal name (two letter abbreviation)
full name of control terminal
process name used for accounting
effective user ID (alias euid)
scheduling priority on return from system call (alias usrpri)
process pointer
user name (from UID)
accumulated user CPU time
vmspace pointer
virtual size in KiB (alias vsize)
wait channel (as a symbolic name)
exit or stop status (valid only for stopped or zombie process)

Some of these keywords are further specified as follows:

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%.
The percentage of real memory used by this process.
Login class associated with the process.
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.
The flags associated with the process as in the include file <sys/proc.h>:
Process may hold a POSIX advisory lock
Has a controlling terminal
Kernel process
Parent is waiting for child to exec/exit
Has started profiling
Has thread in requesting to stop prof
Has had threads (no cleanup shortcuts)
Had set id privileges since last exec
System proc: no sigs, stats or swapping
Threads suspending should exit, not wait
Debugged process being traced
Someone is waiting for us
Working on exiting
Process called exec
Killed, shall go to kernel/user boundary ASAP
Proc has continued from a stopped state
Stopped due to SIGSTOP/SIGTSTP
Stopped because of tracing
Only one thread can continue
Do not kill on memory overcommit
Process pending signals changed
Threads should suspend at user boundary
Process is using HWPMCs
Process is in jail
Stopped for system suspend
Process is in execve(2)
Child process stopped or exited
Always set, unused
Vforked child issued ptrace(PT_TRACEME)
The flags kept in p_flag2 associated with the process as in the include file <sys/proc.h>:
New children get P_PROTECTED
No ptrace(2) attach or coredumps
Keep P2_NOPTRACE on execve(2)
Handles SU ast for kthreads
SIGSTOP from PT_ATTACH not yet handled
SIGTRAP on ENOTCAPABLE
Force enable ASLR
Force disable ASLR
Enable ASLR to consume sbrk area
Force enable implied PROT_MAX
Force disable implied PROT_MAX
Disable stack gap for MAP_STACK
Stack gap disabled after exec
itimers stopped (as part of process stop)
Active ptrace req
Ignore setuid on exec
WX mappings enabled
WxorX enabled after exec
Internal exit early state
REAP_KILL pass handled the process
membarrier private expedited registered
membarrier private expedited sync core registered
membar global expedited registered
The MAC label of the process.
The soft limit on memory used, specified via a call to setrlimit(2).
The exact time the command started, using the ‘%c’ format described in strftime(3).
The name of the lock that the process is currently blocked on. If the name is invalid or unknown, then “???” is displayed.
The login name associated with the session the process is in (see getlogin(2)).
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.
The process scheduling increment (see setpriority(2)).
the real memory (resident set) size of the process in KiB.
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.
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.
The state is given by a sequence of characters, for example, “RWNA”. The first character indicates the run state of the process:

Marks a process in disk (or other short term, uninterruptible) wait.
Marks a process that is idle (sleeping for longer than about 20 seconds).
Marks a process that is waiting to acquire a lock.
Marks a runnable process.
Marks a process that is sleeping for less than about 20 seconds.
Marks a stopped process.
Marks an idle interrupt thread.
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.
The process is in capsicum(4) capability mode.
The process is trying to exit.
Marks a process which is in jail(2). The hostname of the prison can be found in /proc/⟨pid⟩/status.
The process has pages locked in core (for example, for raw I/O).
The process has reduced CPU scheduling priority (see setpriority(2)).
The process is a session leader.
The process' parent is suspended during a vfork(2), waiting for the process to exec or exit.
The process is being traced or debugged.
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.
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:

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

Display information on all system processes:

$ ps -auxw

kill(1), pgrep(1), pkill(1), procstat(1), w(1), kvm(3), libxo(3), strftime(3), xo_parse_args(3), mac(4), procfs(4), pstat(8), sysctl(8), mutex(9)

For historical reasons, the ps utility under FreeBSD supports a different set of options from what is described by and what is supported on non-BSD 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. 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 Version 3 AT&T UNIX 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.

April 28, 2025 release-26.07