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ps - Unix, Linux Command

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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:

TagDescription
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

TagDescription
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 -eopid,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

TagDescription
\$*
  Select all processes. Identical to -e.

\$*
  Select all processes except those that fulfill the specified conditions. (negates the selection) Identical to --deselect.

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

\$*
  Select all processes except session leaders (see getsid(2)) and processes not associated with a terminal.

\$*
  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.

\$*
  Select all processes except session leaders.

\$*
  Select all processes. Identical to -A.

\$*
  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.

\$*
  Restrict the selection to only running processes.

\$*
  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.

\$*
  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

TagDescription
\$*
  Select by command name.
This selects the processes whose executable name is given in cmdlist.

\$*
  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).

\$*
  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.

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

\$*
  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.

\$*
  Select by process ID. Identical to -p and --pid.

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

\$*
  Select by session ID.
This selects the processes with a session ID specified in sesslist.

\$*
  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.

\$*
  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.

\$*
  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.

\$*
  Select by real group ID (RGID) or name. Identical to -G.

\$*
  Select by real user ID (RUID) or name. Identical to -U.

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

\$*
  Select by process ID. Identical to -p and p.

\$*
  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.

\$*
  Select by session ID. Identical to -s.

\$*
  Select by terminal. Identical to -t and t.

\$*
  Select by effective user ID (EUID) or name. Identical to -u and U.

\$*
  Identical to --sid 123.

\$*
  Identical to --pid 123.

OUTPUT FORMAT CONTROL

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

TagDescription
\$*
  extra full format. See the -f option, which -F implies.

\$*
  is 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.

\$*
  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.

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

\$*
  Register format.

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

\$*
  Show different scheduler information for the -l option.

\$*
  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.

\$*
  BSD job control format.

\$*
  jobs format

\$*
  display BSD long format.

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

\$*
  specify user-defined format. Identical to -o and --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.

\$*
  display signal format

\$*
  display user-oriented format

\$*
  display virtual memory format

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

\$*
  display security context format (SELinux, etc.)

\$*
  user-defined format. Identical to -o and o.

\$*
  Display security context format. (for SE Linux)

OUTPUT MODIFIERS

TagDescription
\$*
  show process hierarchy (forest)

\$*
  Specify namelist file. Identical to -n, see -n above.

\$*
  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.

\$*
  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.

\$*
  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.

\$*
  Show the environment after the command.

\$*
  ASCII-art process hierarchy (forest)

\$*
  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.

\$*
  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

\$*
  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

\$*
  Numeric output for WCHAN and USER. (including all types of UID and GID)

\$*
  Wide output. Use this option twice for unlimited width.

\$*
  Wide output. Use this option twice for unlimited width.

\$*
  set screen width

\$*
  set screen width

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

\$*
  ASCII art process tree

\$*
  repeat header lines, one per page of output

\$*
  print no header line at all

\$*
  set screen height

\$*
  set screen height

\$*
  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

\$*
  set screen width

THREAD DISPLAY

TagDescription
\$*
  Show threads as if they were processes

\$*
  Show threads, possibly with LWP and NLWP columns

\$*
  Show threads, possibly with SPID column

\$*
  Show threads after processes

\$*
  Show threads after processes

OTHER INFORMATION

TagDescription
\$*
  List all format specifiers.

\$*
  Print the procps version.

\$*
  Print the procps version.

\$*
  Print a help message.

\$*
  Print debugging info.

\$*
  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.

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

PROCESS FLAGS

The sum of these values is displayed in the "F" column, which is provided by the flags output specifier.
TagDescription
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.
TagDescription
D Uninterruptible sleep (usually IO)
R Running or runnable (on run queue)
S 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.

KEYLONGDESCRIPTION
ccmdsimple name of executable
Cpcpucpu utilization
fflagsflags as in long format F field
gpgrpprocess group ID
Gtpgidcontrolling tty process group ID
jcutimecumulative user time
Jcstimecumulative system time
kutimeuser time
mmin_fltnumber of minor page faults
Mmaj_fltnumber of major page faults
ncmin_fltcumulative minor page faults
Ncmaj_fltcumulative major page faults
osessionsession ID
ppidprocess ID
Pppidparent process ID
rrssresident set size
Rresidentresident pages
ssizememory size in kilobytes
Sshareamount of shared pages
tttythe device number of the controlling tty
Tstart_timetime process was started
Uuiduser ID number
uuseruser name
vvsizetotal VM size in kB
yprioritykernel 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.
CODENORMALHEADER
%Cpcpu%CPU
%GgroupGROUP
%PppidPPID
%UuserUSER
%aargsCOMMAND
%ccommCOMMAND
%grgroupRGROUP
%nniceNI
%ppidPID
%rpgidPGID
%tetimeELAPSED
%uruserRUSER
%xtimeTIME
%yttyTTY
%zvszVSZ

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.

CODEHEADERDESCRIPTION  
%cpu%CPUcpu 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%MEMratio of the process’s resident set size to the physical memory on the machine, expressed as a percentage. (alias pmem).
argsCOMMANDcommand 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.
blockedBLOCKEDmask 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).
bsdstartSTARTtime 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).
bsdtimeTIMEaccumulated 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.
cCprocessor utilization. Currently, this is the integer value of the percent usage over the lifetime of the process. (see %cpu).
caughtCAUGHTmask 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).
classCLSscheduling 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
clsCLSscheduling class of the process. (alias policy, class). Field’s possible values are:
-        not reported
TS        SCHED_OTHER
FF SCHED_FIFO
RR  SCHED_RR
?     unknown value
cmdCMDsee args. (alias args, command).
commCOMMANDcommand name (only the executable name). Modifications to the command name will not be shown. A process marked <defunct> is partly dead, waiting to be fully destroyed by its parent. The output in this column may contain spaces. (alias ucmd, ucomm). See also the args format keyword, the -f option, and the c option.
When specified last, this column will extend to the edge of the display. If ps can not determine display width, as when output is redirected (piped) into a file or another command, the output width is undefined. (it may be 80, unlimited, determined by the TERM variable, and so on) The COLUMNS environment variable or --cols option may be used to exactly determine the width in this case. The w or -w option may be also be used to adjust width.
commandCOMMANDsee args. (alias args, cmd).
cpCPper-mill (tenths of a percent) CPU usage. (see %cpu).
cputimeTIMEcumulative CPU time, "[dd-]hh:mm:ss" format. (alias time).
egidEGIDeffective group ID number of the process as a decimal integer. (alias gid).
egroupEGROUPeffective 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).
eipEIPinstruction pointer.
espESPstack pointer.
etimeELAPSEDelapsed time since the process was started, in the form [[dd-]hh:]mm:ss.
euidEUIDeffective user ID. (alias uid).
euserEUSEReffective 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).
fFflags associated with the process, see the PROCESS FLAGS section. (alias flag, flags).
fgidFGIDfilesystem access group ID. (alias fsgid).
fgroupFGROUPfilesystem 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).
flagFsee f. (alias f, flags).
flagsFsee f. (alias f, flag).
fnameCOMMANDfirst 8 bytes of the base name of the process’s executable file. The output in this column may contain spaces.
fuidFUIDfilesystem access user ID. (alias fsuid).
fuserFUSERfilesystem 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.
gidGIDsee egid. (alias egid).
groupGROUPsee egroup. (alias egroup).
ignoredIGNOREDmask 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).
labelLABELsecurity label, most commonly used for SE Linux context data. This is for the Mandatory Access Control ("MAC") found on high-security systems.
lstartSTARTEDtime the command started.
lwpLWPlwp (light weight process, or thread) ID of the lwp being reported. (alias spid, tid).
niNInice value. This ranges from 19 (nicest) to -20 (not nice to others), see nice(1). (alias nice).
niceNIsee ni. (alias ni).
nlwpNLWPnumber of lwps (threads) in the process. (alias thcount).
nwchanWCHANaddress 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%CPUsee %cpu. (alias %cpu).
pendingPENDINGmask 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).
pgidPGIDprocess group ID or, equivalently, the process ID of the process group leader. (alias pgrp).
pgrpPGRPsee pgid. (alias pgid).
pidPIDprocess ID number of the process.
pmem%MEMsee %mem. (alias %mem).
policyPOLscheduling class of the process. (alias class, cls). Possible values are:
-   not reported
TS        SCHED_OTHER
FF SCHED_FIFO
RR  SCHED_RR
?     unknown value
ppidPPIDparent process ID.
psrPSRprocessor that process is currently assigned to.
rgidRGIDreal group ID.
rgroupRGROUPreal group name. This will be the textual group ID, if it can be obtained and the field width permits, or a decimal representation otherwise.
rssRSSresident set size, the non-swapped physical memory that a task has used (in kiloBytes). (alias rssize, rsz).
rssizeRSSsee rss. (alias rss, rsz).
rszRSZsee rss. (alias rss, rssize).
rtprioRTPRIOrealtime priority.
ruidRUIDreal user ID.
ruserRUSERreal user ID. This will be the textual user ID, if it can be obtained and the field width permits, or a decimal representation otherwise.
sSminimal state display (one character). See section PROCESS STATE CODES for the different values. See also stat if you want additional information displayed. (alias state).
schedSCHscheduling policy of the process. The policies sched_other, sched_fifo, and sched_rr are respectively displayed as 0, 1, and 2.
sessSESSsession ID or, equivalently, the process ID of the session leader. (alias session, sid).
sgi_pPprocessor that the process is currently executing on. Displays "*" if the process is not currently running or runnable.
sgidSGIDsaved group ID. (alias svgid).
sgroupSGROUPsaved group name. This will be the textual group ID, if it can be obtained and the field width permits, or a decimal representation otherwise.
sidSIDsee sess. (alias sess, session).
sigPENDINGsee pending. (alias pending, sig_pend).
sigcatchCAUGHTsee caught. (alias caught, sig_catch).
sigignoreIGNOREDsee ignored. (alias ignored, sig_ignore).
sigmaskBLOCKEDsee blocked. (alias blocked, sig_block).
sizeSZapproximate 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!
spidSPIDsee lwp. (alias lwp, tid).
stackpSTACKPaddress of the bottom (start) of stack for the process.
startSTARTEDtime 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).
start_timeSTARTstarting 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.
statSTATmulti-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.
stateSsee s. (alias s).
suidSUIDsaved user ID. (alias svuid).
suserSUSERsaved 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).
svgidSVGIDsee sgid. (alias sgid).
svuidSVUIDsee suid. (alias suid).
szSZsize 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.
thcountTHCNTsee nlwp. (alias nlwp). number of kernel threads owned by the process.
tidTIDsee lwp. (alias lwp).
timeTIMEcumulative CPU time, "[dd-]hh:mm:ss" format. (alias cputime).
tnameTTYcontrolling tty (terminal). (alias tt, tty).
tpgidTPGIDID 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.
ttTTcontrolling tty (terminal). (alias tname, tty).
ttyTTcontrolling tty (terminal). (alias tname, tt).
ucmdCMDsee comm. (alias comm, ucomm).
ucommCOMMANDsee comm. (alias comm, ucmd).
uidUIDsee euid. (alias euid).
unameUSERsee euser. (alias euser, user).
userUSERsee euser. (alias euser, uname).
vsizeVSZsee vsz. (alias vsz).
vszVSZvirtual memory size of the process in KiB (1024-byte units). Device mappings are currently excluded; this is subject to change. (alias vsize).
wchanWCHANname 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:
TagDescription
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

390like the S/390 OpenEdition ps
aixlike AIX ps
bsdlike FreeBSD ps (totally non-standard)
compaqlike Digital Unix ps
debianlike the old Debian ps
digitallike Tru64 (was Digital Unix, was OSF/1) ps
gnulike the old Debian ps
hplike HP-UX ps
hpuxlike HP-UX ps
irixlike Irix ps
linux***** RECOMMENDED *****
oldlike the original Linux ps (totally non-standard)
os390like OS/390 Open Edition ps
posixstandard
s390like OS/390 Open Edition ps
scolike SCO ps
sgilike Irix ps
solaris2like Solaris 2+ (SunOS 5) ps
sunos4like SunOS 4 (Solaris 1) ps (totally non-standard)
svr4standard
sysvstandard
tru64like Tru64 (was Digital Unix, was OSF/1) ps
unixstandard
unix95standard
unix98standard

SEE ALSO

STANDARDS

This ps conforms to:

TagDescription
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-feedback@lists.sf.net>. No subscription is required or suggested.
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