Linux ps command
Reports a snapshot of the status of currently running processes.
On every UNIX-like operating system, the process status command (ps) displays information about active processes. Every operating system's version of ps is slightly different, so consult your own documentation for specific options.
This documentation describes a version of ps common to many distributions of Linux. It accepts several kinds of options:
- UNIX options, which may be grouped and must be preceded by a dash ("-").
- BSD options, which may be grouped and must not be used with a dash.
- GNU long options, which are preceded by two dashes ("--").
Options of different types may be freely mixed, but might cause conflicts. There are some synonymous options, which are functionally identical, due to the many standards and ps implementations that ps is compatible with.
Note that "ps -aux" is different than "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, ps may interpret the command as "ps aux" instead and print a warning. This behavior is intended to aid in the transitioning of legacy scripts, but it is 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 arguments (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.
Options: Simple Process Selection
|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.|
|-A||Select all processes. Identical to -e.|
|-a||Select all processes except both session leaders and processes not associated with a terminal.|
|-d||Select all processes except session leaders.|
|--deselect||Select all processes except those that fulfill the specified conditions (negates the selection). Identical to -N.|
|-e||Select all processes. Identical to -A.|
|g||Really all processes, 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.|
|-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.|
|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.|
Options: Process Selection By List
These options accept a single argument in the form of a blank-separated or comma-separated list, and they can be used multiple times. For example:
ps -p "1 2" -p 3,4
...is a valid command.
Options which select processes by list are as follows:
|-123||Identical to "--pid 123".|
|123||Identical to "--pid 123".|
|-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.|
|-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.|
|--Group grplist||Select by real group ID (RGID) or name. Identical to -G.|
|--group grplist||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. The -g option is often an alternative to --group.|
|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.|
|--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.|
|-s sesslist||Select by session ID. This selects the processes with a session ID specified in sesslist.|
|--sid sesslist||Select by session ID. Identical to -s.|
|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.|
|--tty ttylist||Select by terminal. Identical to -t and t.|
|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. Identical to -u and --user.|
|-U userlist||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.|
|-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. Identical to U and --user.
|--User userlist||Select by real user ID (RUID) or name. Identical to -U.|
|--user userlist||Select by effective user ID (EUID) or name. Identical to -u and U.|
Options: Output Format Control
These options are used to choose the information displayed by ps. The output may differ from version to version.
|-c||Show different scheduler information for the -l option.|
|--context||Display security context format (when using SE Linux).|
|-f||Do 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.|
|-F||Extra full format. See the -f option, which -F implies.|
|--format format||user-defined format. Identical to -o and o.|
|j||BSD job control format.|
|l||Display BSD long format.|
|-l||Long format. The -y option is often useful with this.|
|-M||Add a column of security data. Identical to Z (for SE Linux).|
|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.|
|-O format||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.|
|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,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.|
|s||Display signal format.|
|u||Display user-oriented format.|
|v||Display virtual memory format.|
|-y||Do not show flags; show rss in place of addr. This option can only be used with -l.|
|Z||Add a column of security data. Identical to -M (for SE Linux).|
Options: Output Modifiers
|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 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.|
|--cols n||Set screen width.|
|--columns n||Set screen width.|
|--cumulative||Include some dead child process data (as a sum with the parent).|
|e||Show the environment after the command.|
|f||ASCII art process hierarchy (as many trees, also referred to as a "forest").|
|--forest||ASCII art process tree.|
|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. Linux ps follows the standard 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.|
|-H||Show process hierarchy (forest).|
|--headers||Repeat header lines, one per page of output.|
|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.
ps axk comm o comm,args
ps kstart_time -ef
|--lines n||Set screen height.|
|-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:
|n||Numeric output for WCHAN and USER (including all types of UID and GID).|
|N namelist||Specify namelist file. Identical to -n; see -n, above.|
|--no-headers||Print no header line at all. --no-heading is an alias for this option.|
|O order||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.
|--rows n||Set screen height.|
|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.|
|--sort 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 k. For example: "ps jax --sort=uid, -ppid,+pid"|
|w||Wide output. Use this option twice for unlimited width.|
|-w||Wide output. Use this option twice for unlimited width.|
|--width n||Set screen width.|
Options: Thread Display
|H||Show threads as if they were processes.|
|-L||Show threads, possibly with LWP and NLWP columns.|
|m||Show threads after processes.|
|-m||Show threads after processes.|
|-T||Show threads, possibly with SPID column.|
Options: Displaying Other Information
|--help section||Print a help message. The section argument can be one of simple, list, output, threads, misc or all. The argument can be shortened to one of the underlined letters as in: s|l|o|t|m|a.|
|--info||Print debugging info.|
|L||List all format specifiers.|
|V||Print the procps-ng version.|
|-V||Print the procps-ng version.|
|--version||Print the procps-ng version.|
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 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.
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)|
|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 command if you want to sort the cooked values.
|c||cmd||simple name of executable|
|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|
|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|
|P||ppid||parent process ID|
|r||rss||resident set size|
|s||size||memory size in kilobytes|
|S||share||amount of shared pages|
|t||tty||the device number of the controlling tty|
|T||start_time||time process was started|
|U||uid||user ID number|
|v||vsize||total VM size in KiB|
|y||priority||kernel scheduling priority|
AIX Format Descriptors
ps supports AIX format descriptors, which work somewhat like the formatting codes of printf. For example, the normal default output can be produced with this:
ps -eo "%p %y %x %c"
AIX Format Descriptors are as follows:
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".
ps tries to recognize most of the keywords used in other implementations of ps.
The following user-defined format specifiers may contain spaces:
Some keywords may not be available for sorting.
|%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 arguments 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 signals. According to the width of the field, a 32 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:SS" (where Mmm is the three letters of the month). See also lstart, start, start_time, and stime.|
|bsdtime||TIME||accumulated 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.|
|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 signals. According to the width of the field, a 32 or 64 bits mask in hexadecimal format is displayed. (alias: sig_catch, sigcatch).|
|cgroup||CGROUP||display control groups to which the process belongs.|
scheduling class of the process. (alias: policy, cls). Field's possible values are:
|cls||CLS||scheduling class of the process. (alias: policy, class). Field's possible values are the same as for class, listed above.|
|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, 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.
|command||COMMAND||See args. (alias: args, command).|
|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: <bgid>).|
|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).|
|etime||ELAPSED||elapsed time since the process was started, in the form "[[DD-]hh:]mm:ss".|
|etimes||ELAPSED||elapsed time since the process was started, in seconds.|
|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 group 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 signals. According to the width of the field, a 32 or 64 bits 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. See also bsdstart, start, start_time, and stime.|
|lwp||LWP||light weight process (thread) ID of the dispatchable entity (alias: spid, tid). See tid for additional information.|
|maj_flt||MAJFLT||The number of major page faults that have occurred with this process.|
|min_flt||MINFLT||The number of minor page faults that have occurred with this process.|
|ni||NI||nice value. This ranges from 19 (nicest) to -20 (not nice to others). (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 signals. 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 or 64 bits 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||a number representing the process ID (alias: tgid).|
|pmem||%MEM||see %mem. (alias: %mem).|
|policy||POL||scheduling class of the process. (alias: class, cls). Possible values are:
|ppid||PPID||parent process ID.|
|pri||PRI||priority of the process. Higher number means lower priority.|
|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).|
|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 additional information displayed. (alias: state).|
|sched||SCH||scheduling policy of the process. The policies SCHED_OTHER (SCHED_NORMAL), SCHED_FIFO, SCHED_RR, SCHED_BATCH, SCHED_ISO, and SCHED_IDLE are respectively displayed as 0, 1, 2, 3, 4, and 5.|
|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||SIZE||approximate amount of swap space that would be required if the process were to dirty all writable pages and then be swapped out. This approximation 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). See also lstart, bsdstart, start_time, and stime.|
|start_time||START||starting 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. See also bsdstart, start, lstart, and stime.|
|stat||STAT||multi-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.|
|state||S||see s. (alias: s).|
|suid||SUID||saved user ID. (alias: svuid).|
|supgid||SUPGID||group ids of supplementary groups, if any.|
|supgrp||SUPGRP||group names of supplementary groups, if any.|
|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.|
|tgid||TGID||a number representing the thread group to which a task belongs (alias: pid). It is the process ID of the thread group leader.|
|thcount||THCNT||see nlwp. (alias: nlwp). number of kernel threads owned by the process.|
|tid||TID||the unique number representing a dispatacable entity (alias: lwp, spid). This value may also appear as: a process ID (pid); a process group ID (pgrp); a session ID for the session leader (sid); a thread group ID for the thread group leader (tgid); and a tty process group ID for the process group leader (tpgid).|
|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).|
|user||USER||see euser. (alias: euser, uname).|
|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.|
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.|
|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.
The following "personalities" affect the output of ps:
|390||like the OS/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||This is the recommended personality for ps.|
|old||like the original Linux ps (totally non-standard)|
|os390||like OS/390 Open Edition ps|
|posix||The personality which conforms to the 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).|
|tru64||like Tru64 (was Digital Unix, was OSF/1) ps.|
To see every process running on the system, using the standard syntax:
To see every process on the system, using BSD syntax:
To display a process tree:
To get info about threads:
To get security info:
ps -eo euser,ruser,suser,fuser,f,comm,label
To see every process running as root (real and 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 -Ao pid,tt,user,fname,tmout,f,wchan
ps -C syslogd -o pid=
Print only the name of process ID 15:
ps -p 15 -o comm=
bg — Resume a suspended program without bringing it to the foreground.
free — Display the amount of free and used memory.
fuser — Identify processes using files or sockets.
kill — Send a signal to a process, affecting its behavior or killing it.
killall — Kill processes by name.
nice — Invoke a command with an altered scheduling priority.
pagesize — Display the size of a page of memory in bytes.
pgrep — Look up processes based on the name or other attributes.
priocntrl — Display or set scheduling parameters of a processes under Solaris.
pstree — Display processes in a tree format.
top — Display a sortable, continually-updated list of processes.
tty — Print the file name of the terminal connected to standard input.
uptime — Display information about how long the system has been running.
who — Display information about how long the system has been running.