The ps command prints information about active processes. Without options, ps prints information about processes that have the same effective user ID and the same controlling terminal as the invoker. The output contains only the process ID, terminal identifier, cumulative execution time, and the command name. Otherwise, the information that is displayed is controlled by the options.

Some options accept lists as arguments. Items in a list can be either separated by commas or else enclosed in quotes and separated by commas or spaces. Values for proclist and grplist must be numeric.

The following options are supported:

-a

Lists information about all processes most frequently requested: all those except session leaders and processes not associated with a terminal.

-A

Lists information for all processes. Identical to -e, below.

-c

Prints information in a format that reflects scheduler properties as described in priocntl(1). The -c option affects the output of the -f and -l options, as described below.

-d

Lists information about all processes except session leaders.

-e

Lists information about every process now running.

-f

Generates a full listing. (See below for significance of columns in a full listing.)

-g grplist

Lists only process data whose group leader's ID number(s) appears in grplist. (A group leader is a process whose process ID number is identical to its process group ID number.)

-G gidlist

Lists information for processes whose real group ID numbers are given in gidlist. The gidlist must be a single argument in the form of a blank- or comma-separated list.

-j

Prints session ID and process group ID.

-l

Generates a long listing. (See below.)

-L

Prints information about each light weight process (lwp) in each selected process. (See below.)

-n namelist

Specifies the name of an alternative system namelist file in place of the default. This option is accepted for compatibility, but is ignored.

-o format

Prints information according to the format specification given in format. This is fully described in DISPLAY FORMATS. Multiple -o options can be specified; the format specification will be interpreted as the space-character-separated concatenation of all the format option-arguments.

-ps proclist

Lists only process data whose process ID numbers are given in proclist.

-P

Prints the number of the processor to which the process or lwp is bound, if any, under an additional column header, PSR.

-s sidlist

Lists information on all session leaders whose IDs appear in sidlist.

-t term

Lists only process data associated with term. Terminal identifiers are specified as a device file name, and an identifier. For example, term/a, or pts/0.

-u uidlist

Lists only process data whose effective user ID number or login name is given in uidlist. In the listing, the numerical user ID will be printed unless you give the -f option, which prints the login name.

-U uidlist

Lists information for processes whose real user ID numbers or login names are given in uidlist. The uidlist must be a single argument in the form of a blank- or comma-separated list.

-y

Under a long listing (-l), omits the obsolete F and ADDR columns and includes an RSS column to report the resident set size of the process. Under the -y option, both RSS and SZ (see below) will be reported in units of kilobytes instead of pages.

Many of the options shown are used to select processes to list. If any are specified, the default list will be ignored and ps will select the processes represented by the inclusive OR of all the selection-criteria options.

Under the -f option, ps tries to determine the command name and arguments given when the process was created by examining the user block. Failing this, the command name is printed, as it would have appeared without the -f option, in square brackets.

The column headings and the meaning of the columns in a ps listing are given below; the letters f and l indicate the option (full or long, respectively) that causes the corresponding heading to appear; all means that the heading always appears. Note: These two options determine only what information is provided for a process; they do not determine which processes will be listed.

F (l)

Flags (hexadecimal and additive) associated with the process. These flags are available for historical purposes; no meaning should be currently ascribed to them.

S (l)

The state of the process:

O

Process is running on a processor.

S

Sleeping: process is waiting for an event to complete.

R

Runnable: process is on run queue.

Z

Zombie state: process terminated and parent not waiting.

T

Process is stopped, either by a job control signal or because it is being traced.

UID (f,l)

The effective user ID number of the process (the login name is printed under the -f option).

PID (all)

The process ID of the process (this datum is necessary in order to kill a process).

PPID (f,l)

The process ID of the parent process.

C (f,l)

Processor utilization for scheduling (obsolete). Not printed when the -c option is used.

CLS (f,l)

Scheduling class. Printed only when the -c option is used.

PRI (l)

The priority of the process. Without the -c option, higher numbers mean lower priority. With the -c option, higher numbers mean higher priority.

NI (l)

Nice value, used in priority computation. Not printed when the -c option is used. Only processes in the certain scheduling classes have a nice value.

ADDR (l)

The memory address of the process.

SZ (l)

The total size of the process in virtual memory, including all mapped files and devices, in pages. See pagesize(1).

WCHAN (l)

The address of an event for which the process is sleeping (if blank, the process is running).

STIME (f)

The starting time of the process, given in hours, minutes, and seconds. (A process begun more than twenty-four hours before the ps inquiry is executed is given in months and days.)

TTY (all)

The controlling terminal for the process (the message, ?, is printed when there is no controlling terminal).

TIME (all)

The cumulative execution time for the process.

CMD (all)

The command name (the full command name and its arguments, up to a limit of 80 characters, are printed under the -f option).

The following two additional columns are printed when the -j option is specified:

PGID

The process ID of the process group leader.

SID

The process ID of the session leader.

The following two additional columns are printed when the -L option is specified:

LWP

The lwp ID of the lwp being reported.

NLWP

The number of lwps in the process (if -f is also specified).

Under the -L option, one line is printed for each lwp in the process and the time-reporting fields STIME and TIME show the values for the lwp, not the process. A traditional single-threaded process contains only one lwp.

A process that has exited and has a parent, but has not yet been waited for by the parent, is marked <defunct>.

o format

See environ(5) for descriptions of the following environment variables that affect the execution of ps: LC_CTYPE, LC_MESSAGES, LC_TIME, and NLSPATH.

COLUMNS

Override the system-selected horizontal screen size, used to determine the number of text columns to display.

The following exit values are returned:

0

Successful completion.

>0

An error occurred.

/dev/pts/*

/dev/term/*

terminal (``tty'') names searcher files

/etc/passwd

UID information supplier

/proc/*

process control files

/tmp/ps_data

internal data structure

See attributes(5) for descriptions of the following attributes:

kill(1), nice(1), pagesize(1), pgrep(1), priocntl(1), who(1), getty(1M), proc(4), ttysrch(4), attributes(5), environ(5)

Things can change while ps is running. The snapshot it gives is true only for a split-second, and it may not be accurate by the time you see it. Some data printed for defunct processes is irrelevant.

If no options to select processes are specified, ps will report all processes associated with the controlling terminal. If there is no controlling terminal, there will be no report other than the header.

ps -ef or ps -o stime may not report the actual start of a tty login session, but rather an earlier time, when a getty was last respawned on the tty line.

ps is CSI-enabled except for login names (usernames).