PS(1)

💖 PS(1) 💖

General Commands Manual. Hey bestie, we're doing ps today. It's giving process snapshot energy. 🫶

✨ NAME ✨

ps — report a snapshot of the current processes. That's the whole point, no cap. 💅

✨ SYNOPSIS ✨

ps [option ...]

✨ 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 instead. 🎀

This version of ps 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 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. 🌈

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 ✨

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 -Ao pid,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 -q 42 -o comm=

🌸 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 (see getsid(2)) 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, 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.

🌈 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 🎀

• 123 — Identical to --pid 123.
• +123 — Identical to --sid 123.
• -123 — Select by process group ID (PGID).
• -C cmdlist — Select by command name. This selects the processes whose executable name is given in cmdlist. NOTE: The command name is not the same as the command line. Previous versions of procps and the kernel truncated this command name to 15 characters. This limitation is no longer present in both. If you depended on matching only 15 characters, you may no longer get a match.
• -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, see getgid(2).
• -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 grplist. The effective group ID describes the group whose file access permissions are used by the process (see getegid(2)). 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.
• q pidlist — Select by process ID (quick mode). Identical to -q and --quick-pid.
• -q pidlist — Select by PID (quick mode). This selects the processes whose process ID numbers appear in pidlist. With this option ps reads the necessary info only for the pids listed in the pidlist and doesn't apply additional filtering rules. The order of pids is unsorted and preserved. No additional selection options, sorting and forest type listings are allowed in this mode. Identical to q and --quick-pid.
• --quick-pid pidlist — Select by process ID (quick mode). Identical to -q and q.
• -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 (see geteuid(2)). 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, see getuid(2).
• -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 (see geteuid(2)). 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.

✨ OUTPUT FORMAT CONTROL ✨

okay bestie this is the section where you get to decide what actually shows up on screen 💅 these options pick which info ps hands you. heads up tho — the output can differ depending on personality. and those things in brackets at the end of each description? those are the format equivalents, like the shortcut version of the same vibe. 🎀

• -c — shows different scheduler information for the -l option. (-O cls,pri).
• --context — displays the security context format (for SELinux). (-o pid,context,cmd).
• -f — do the full-format listing. you can combine this with tons of other Unix-style options to tack on extra columns, and it also makes the command arguments print out. when you use it with -L, the NLWP (number of threads) and LWP (thread ID) columns get added. see the c option, the format keyword args, and the format keyword comm. (-o uid,pid,ppid,c,stime,tty,time,cmd).
• -F — extra full format. see the -f option, which -F implies. (-o uid,pid,ppid,c,sz,rss,psr,stime,tty,time,cmd).
• --format format — user-defined format. literally identical to -o and o.
• j — BSD job control format. (-o ppid,pid,pgid,sid,tty,tpgid,stat,uid,time,cmd a)
• -j — jobs format. (-o pid,pgid,sid,tty,time,ucmd)
• l — display BSD long format. (-o f,uid,pid,ppid,pri,ni,vsz,rss,wchan,stat,tty,time,cmd a)
• -l — long format. the -y option is often useful alongside this one. (-o f,uid,pid,ppid,c,pri,ni,addr,sz,wchan,tty,time,ucmd)
• -M — add a column of security data. identical to Z (for SELinux). (-o context,pid,tty,time,ucmd)
• O format — this one is preloaded o (overloaded, iconic behavior honestly). the BSD O option can act like -O (user-defined output format with some common fields predefined) OR it can be used to specify sort order. heuristics are used to figure out which behavior you're getting. to make sure you actually get the behavior you want (sorting or formatting), specify the option some other way (e.g., with -O or --sort). when it's used as a formatting option, it's 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, the main character fr. 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) however you want. if all column headers are empty (ps -o pid= -o comm=) then the header line will not be output at all. column width will increase as needed for wide headers — you can use this 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.
• -P — add a column showing psr. (-o pid,psr,s,tty,time,ucmd)
• s — display signal format. (-o uid,pid,pending,blocked,ignored,caught,stat,tty,bsdtime,cmd a)
• u — display user-oriented format. (-o user,pid,pcpu,pmem,vsz,rss,tty,stat,start_time,bsdtime,args a)
• v — display virtual memory format. (-o pid,tty,stat,bsdtime,majflt,trs,drs,rss,pmem,args a)
• X — register format. (-o pid,stackp,esp,eip,tmout,alarm,stat,tty,bsdtime,args a)
• -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 SELinux).

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🦋 OUTPUT MODIFIERS 🦋

these ones tweak the vibe of what you already got — headers, widths, delimiters, sorting, all that good stuff ✨

• 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's 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).
• -D format — set the date format of the lstart field to format. this format is parsed by strftime(3) and should be a maximum of 24 characters to not mis-align columns.
• --date-format format — identical to -D.
• --delimiter delim — set the delimiter between each column to delim instead of variable space. must be a single character.
• e — show the environment after the command.
• f — ASCII art process hierarchy (forest). 🌲
• --forest — ASCII art process tree.
• h — no header. (or, one header per screen in the BSD personality). okay so the h option is lowkey 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.
• -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 the default direction is increasing numerical or lexicographic order. identical to --sort.

examples, bestie:

ps jaxkuid,-ppid,+pid
ps axk comm o comm,args
ps kstart_time -ef

• --lines n — set screen height.
• n — numeric output for WCHAN and USER (including all types of UID and GID).
• --no-headers — print no header line at all. --no-heading is an alias for this option.
• O order — sorting order (overloaded, again 💀). 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, the 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 it 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 the default direction is increasing numerical or lexicographic order. identical to k. for example: ps jax --sort=uid,-ppid,+pid
• --signames — show signal masks using abbreviated signal names and expands the column. if the column width cannot show all signals, the column will end with a plus "+". columns with only a hyphen have no signals.
• 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.

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🧚 THREAD DISPLAY 🧚

threads thread threads — let's peek at them 🫶

• 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.

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💜 OTHER INFORMATION 💜

the little extras, the side quests, the 🍓 on top

• --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.

📝 NOTES 📝

okay bestie, storytime: this ps works by reading the virtual files in /proc. that's it, that's the whole trick. it does not need to be setuid kmem and it does not need any privileges to run. so do not give this ps any special permissions, fr fr. 🙅‍♀️

CPU usage? currently expressed as the percentage of time spent running during the entire lifetime of a process. is that ideal? no. does it conform to the standards that ps otherwise conforms to? also no. 😭 and it's unlikely to add up to exactly 100%. lowkey unhinged but that's the vibe.

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 (the 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. no cap.

if the length of the username is greater than the width of the display column, the username will be truncated. 😬 see the -o and -O formatting options to customize length.

and now the big one, listen up: command options such as ps -aux are not recommended as it is a confusion of two different standards. according to the POSIX and Unix standards, the above command asks to display all processes with a TTY (generally the commands users are running) plus all processes owned by a user named x. and if that user doesn't exist? then ps will assume you really meant "ps aux". so it works by accident. iconic behavior honestly. 💀

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🚩 PROCESS FLAGS 🚩

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

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🌈 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 I/O)
• I — idle kernel thread
• R — running or runnable (on run queue)
• S — interruptible sleep (waiting for an event to complete)
• T — stopped by job control signal
• t — stopped by debugger during the tracing
• W — paging (not valid since Linux 2.6)
• 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 I/O)
• s — is a session leader
• l — is multi-threaded (using CLONE_THREAD, like NPTL pthreads do)
• + — is in the foreground process group

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🦕 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. 🍳

• c / cmd — simple name of executable
• C / pcpu — cpu utilization
• 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
• k / utime — user 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
• o / session — session ID
• p / pid — process ID
• P / ppid — parent process ID
• r / rss — resident set size
• R / resident — resident pages
• s / size — memory size in kibibytes
• 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
• u / user — user name
• v / vsize — total VM size in KiB
• y / priority — kernel scheduling priority

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🤖 AIX FORMAT DESCRIPTORS 🤖

this ps supports AIX format descriptors, which work somewhat like the formatting codes of printf(1) and printf(3). the NORMAL codes are described in the next section. ✨

• %C — normal: pcpu — header: %CPU
• %G — normal: group — header: GROUP
• %P — normal: ppid — header: PPID
• %U — normal: user — header: USER
• %a — normal: args — header: COMMAND
• %c — normal: comm — header: COMMAND
• %g — normal: rgroup — header: RGROUP
• %n — normal: nice — header: NI
• %p — normal: pid — header: PID
• %r — normal: pgid — header: PGID
• %t — normal: etime — header: ELAPSED
• %u — normal: ruser — header: RUSER
• %x — normal: time — header: TIME
• %y — normal: tty — header: TTY
• %z — normal: vsz — header: VSZ

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👑 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.

• %cpu — header %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 — header %MEM — ratio of the process's resident set size to the physical memory on the machine, expressed as a percentage. (alias pmem).
• ag_id — header AGID — the autogroup identifier associated with a process which operates in conjunction with the CFS scheduler to improve interactive desktop performance.
• ag_nice — header AGNI — the autogroup nice value which affects scheduling of all processes in that group.
• args — header COMMAND — a command with all its arguments as a string. modifications to the arguments may be shown. the column contents may include 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 instead reports 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 the 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, which can be overridden with the --cols, --columns or --width 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 — header BLOCKED — mask of the blocked signals, see signal(7). according to the width of the field, a 32 or 64-bit mask in hexadecimal format is displayed, unless the --signames option is used. (alias sig_block, sigmask).
• bsdstart — header 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 — header 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 — header C — processor utilization. currently, this is the integer value of the percent usage over the lifetime of the process. (see %cpu).
• caught — header CAUGHT — mask 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, unless the --signames option is used. (alias sig_catch, sigcatch).
• cgname — header CGNAME — display name of control groups to which the process belongs.
• cgroup — header CGROUP — display control groups to which the process belongs.
• cgroupns — header CGROUPNS — unique inode number describing the namespace the process belongs to. see namespaces(7).
• class — header CLS — scheduling class of the process. (alias policy, cls). field's possible values are:
• cls, CLS — the scheduling class of the process. It also answers to policy and cls (yes, it's aliased to itself, main character behaviour honestly). The possible values are:
  • - — not reported
  • TS — SCHED_OTHER
  • FF — SCHED_FIFO
  • RR — SCHED_RR
  • B — SCHED_BATCH
  • ISO — SCHED_ISO
  • IDL — SCHED_IDLE
  • DLN — SCHED_DEADLINE
  • ? — unknown value
• cmd, CMD — go look at args. That's it, that's the entry. (alias args, command).
• comm, COMMAND — the command name, but only the executable name part. Heads up: the output in this column may contain spaces, so don't come for me when your parsing gets weird. (alias ucmd, ucomm). Also go read the args format keyword, the -f option, and the c option, they're all in this together.

And here's the spicy bit: when you put this column last, it stretches all the way to the edge of the display. But if ps can't figure out the display width — like when the output gets redirected or piped into a file or another command — then the output width is undefined. It might be 80, it might be unlimited, it might be whatever the TERM variable says, who even knows. To pin the width down exactly, use the COLUMNS environment variable or the --cols option. The w or -w option can also be used to adjust the width. 🎀

• command, COMMAND — see args. (alias args, command).
• cp, CP — per-mill (that's tenths of a percent) CPU usage. (see %cpu).
• cpu, CPU — see psr. (alias cpuid, lastcpu, psr).
• cpuid, CPUID — see psr. (alias cpu, lastcpu, psr).
• cputime, TIME — cumulative CPU time, formatted like "[DD-]hh:mm:ss". (alias time).
• cputimes, TIME — cumulative CPU time but in seconds. (alias times).
• cuc, %CUC — the CPU utilization of a process, dead children included (yes, really), in an extended "##.###" format. (see also %cpu, c, cp, cuu, pcpu).
• cuu, %CUU — the CPU utilization of a process in an extended "##.###" format. (see also %cpu, c, cp, cuc, pcpu).
• docker, DOCKER — the abbreviated id of the docker container that a task is running inside of. If the process isn't in a container, you get a dash ('-'). Simple as that. 🐳
• drs, DRS — data resident set size, aka the amount of private memory a process has reserved. It's also known as DATA. This memory might not be mapped to rss yet, but it will always be included in the vsz amount.
• egid, EGID — the effective group ID number of the process, as a decimal integer. (alias gid).
• egroup, EGROUP — the effective group ID of the process. You get the textual group ID if it can be obtained and the field width permits it, otherwise you get a decimal representation. (alias group).
• eip, EIP — instruction pointer. Lowkey important caveat: as of kernel 4.9.xx it will be zeroed out unless the task is exiting or being core dumped. 😭
• esp, ESP — stack pointer. Same deal as eip: as of kernel 4.9.xx it gets zeroed out unless the task is exiting or being core dumped.
• 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.
• environ, ENVIRON — environment variables for the process.
• euid, EUID — effective user ID (alias uid).
• euser, EUSER — effective user name. You get the textual user ID if it can be obtained and the field width permits it, otherwise it falls back to a decimal representation. The n option can force that decimal representation. (alias uname, user).
• exe, EXE — path to the executable. Super handy when the path can't be printed through the cmd, comm or args format options. ✨
• f, F — flags associated with the process. Go read the PROCESS FLAGS section. (alias flag, flags).
• fds, FDS — total open file descriptors.
• fgid, FGID — filesystem access group ID. (alias fsgid).
• fgroup, FGROUP — filesystem access group ID. Textual group ID if it can be obtained and the field width permits, decimal representation otherwise. (alias fsgroup).
• flag, F — see f. (alias f, flags).
• flags, F — see f. (alias f, flag).
• fname, COMMAND — the first 8 bytes of the base name of the process's executable file. And again, the output in this column may contain spaces.
• fuid, FUID — filesystem access user ID. (alias fsuid).
• fuser, FUSER — filesystem access user ID. Textual user ID if it can be obtained and the field width permits, decimal representation otherwise.
• gid, GID — see egid. (alias egid).
• group, GROUP — see egroup. (alias egroup).
• htprv, HTPRV — the amount of private memory backed by hugetlbfs page which is not counted in the rss or pss format options.
• htshr, HTSHR — the amount of shared memory backed by hugetlbfs page which is not counted in the rss or pss format options.
• ignored, IGNORED — mask of the ignored signals, see signal(7). Depending on how wide the field is, you get a 32 or 64 bits mask in hexadecimal format — unless the --signames option is used. (alias sig_ignore, sigignore).
• ipcns, IPCNS — unique inode number describing the namespace the process belongs to. See namespaces(7).
• label, LABEL — security label, most commonly used for SELinux context data. This one's for the Mandatory Access Control ("MAC") situation found on high-security systems. 🔐
• lastcpu, C — see psr. (alias cpu, cpuid, psr).
• lstart, STARTED — the time the command started. It comes in the form "DDD mmm HH:MM:SS YYY" unless the -D option changed it.
• lsession, SESSION — displays the login session identifier of a process, but only if systemd support has been included. (conditional queen 💅)
• luid, LUID — displays the Login ID associated with a process.
• lwp, LWP — light weight process (thread) ID of the dispatchable entity. (alias spid, tid). See tid for additional information.
• lxc, LXC — the name of the lxc container a task is running inside of. If the process isn't in a container, you get a dash ('-').
• machine, MACHINE — displays the machine name for processes assigned to a VM or container, if systemd support has been included.
• 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.
• mntns, MNTNS — unique inode number describing the namespace the process belongs to. See namespaces(7).
• netns, NETNS — unique inode number describing the namespace the process belongs to. See namespaces(7).
• ni, NI — nice value. This ranges from 19 (nicest) to -20 (not nice to others), see nice(1). (alias nice).
• nice, NI — see ni. (alias ni). (the alias circle continues, we stan a mutual)
• nlwp, NLWP — number of lwps (threads) in the process. (alias thcount).
• numa, NUMA — the node associated with the most recently used processor. A -1 means that NUMA information is unavailable.
• nwchan, WCHAN — address of the kernel function where the process is sleeping. Use wchan instead if you want the actual kernel function name.
• oom, OOM — Out of Memory Score. The value ranges from 0 to +1000, and it's what's used to pick the task(s) to kill when memory is exhausted. 💀
• oomadj, OOMADJ — Out of Memory Adjustment Factor. This value gets added to the current out of memory score, which is then used to decide which task to kill when memory is exhausted.
• ouid, OWNER — displays the Unix user identifier of the owner of the session of a process, if systemd support has been included.
• pcap, PCAP — Permitted Capabilities of the process, displayed as a hexadecimal bitmask. See capabilities(7).
• pcaps, PCAPS — Permitted Capabilities of the process, displayed as a string of capability names. See capabilities(7).
• pcpu, %CPU — see %cpu. (alias %cpu).
• pending (PENDING) — the mask of the pending signals, bestie 💅. Peep signal(7) for the whole lore. Lowkey important: signals pending on the process are a completely different vibe from signals pending on individual threads, so if you wanna see both, hit the m option or the -m option. Depending on how wide the field is, you get a 32 or 64 bit mask in hexadecimal, unless you used --signames. (alias sig). 🦋
• pgid (PGID) — process group ID, which is literally the same thing as the process ID of the process group leader. two names, one truth ✨. (alias pgrp).
• pgrp (PGRP) — see pgid. (alias pgid).
• pid (PID) — a number representing the process ID (alias tgid). the classic, the icon.
• pidns (PIDNS) — unique inode number describing the namespace the process belongs to. See namespaces(7). 🌸
• pmem (%MEM) — see %mem. (alias %mem).
• policy (POL) — scheduling class of the process. (alias class, cls). Possible values are:
  • - not reported
  • TS SCHED_OTHER
  • FF SCHED_FIFO
  • RR SCHED_RR
  • B SCHED_BATCH
  • ISO SCHED_ISO
  • IDL SCHED_IDLE
  • DLN SCHED_DEADLINE
  • ? unknown value
• ppid (PPID) — parent process ID. the mother of all processes fr.
• pri (PRI) — priority of the process. Higher number means higher priority, periodt.
• psr (PSR) — processor that process last executed on. (alias cpu, cpuid, lastcpu).
• pss (PSS) — Proportional share size, the non-swapped physical memory, with shared memory proportionally accounted to all tasks mapping it. the math is mathing 📐.
• rbytes (RBYTES) — Number of bytes which this process really did cause to be fetched from the storage layer.
• rchars (RCHARS) — Number of bytes which this task has caused to be read from storage.
• 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. 🙈
• rops (ROPS) — Number of read I/O operations—that is, system calls such as read(2) and pread(2).
• rss (RSS) — resident set size, the non-swapped physical memory that a task has used (in kibibytes). (alias rssize, rsz).
• rssize (RSS) — see rss. (alias rss, rsz).
• rsz (RSZ) — see rss. (alias rss, rssize).
• rtprio (RTPRIO) — realtime priority.
• 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, SCHED_IDLE and SCHED_DEADLINE are respectively displayed as 0, 1, 2, 3, 4, 5 and 6. slay 💅
• seat (SEAT) — displays the identifier associated with all hardware devices assigned to a specific workplace, if systemd support has been included.
• 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. Heads up bestie, this number is very rough!
• slice (SLICE) — displays the slice unit which a process belongs to, if systemd support has been included.
• 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 bsdstart, start, 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).
• stime (STIME) — see start_time. (alias start_time).
• suid (SUID) — saved user ID. (alias svuid).
• supgid (SUPGID) — group ids of supplementary groups, if any. See getgroups(2).
• supgrp (SUPGRP) — group names of supplementary groups, if any. See getgroups(2).
• 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 dispatchable entity (alias spid, tid). 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).
• timens (TIMENS) — Unique inode number describing the namespace the process belongs to. See namespaces(7).
• times (TIME) — cumulative CPU time in seconds (alias cputimes).
• 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.
• trs (TRS) — text resident set size, the amount of physical memory devoted to executable code.
• 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).
• unit (UNIT) — displays unit which a process belongs to, if systemd support has been included.
• user (USER) — see euser. (alias euser, uname).
• userns (USERNS) — Unique inode number describing the namespace the process belongs to. See namespaces(7).
• uss (USS) — Unique set size, the non-swapped physical memory, which is not shared with an another task.
• utsns (UTSNS) — Unique inode number describing the namespace the process belongs to. See namespaces(7).
• uunit (UUNIT) — displays user unit which a process belongs to, if systemd support has been included.
• 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).
• wbytes (WBYTES) — Number of bytes which this process caused to be sent to the storage layer.
• wcbytes (WCBYTES) — Number of cancelled write bytes.
• wchan, WCHAN — the name of the kernel function your process is snoozing inside. it's giving "what is it waiting on" but make it ✨mysterious✨
• wchars, WCHARS — how many bytes this task has caused, or is about to cause, to be written to disk. little bookkeeper energy 💾
• wops, WOPS — number of write I/O operations, aka system calls like write(2) and pwrite(2). bestie is counting her syscalls fr fr

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🌸 ENVIRONMENT VARIABLES 🌸

okay so these env vars could affect ps, and by "could" i mean they absolutely will, no cap:

• COLUMNS — override the default display width. make it as wide as your dreams 🦋
• LINES — override the default display height. tall or short, she's flexible 💅
• PS_PERSONALITY — set it to one of posix, old, linux, bsd, sun, digital... (go check the PERSONALITY section below, i got you 🫶)
• CMD_ENV — set it to one of posix, old, linux, bsd, sun, digital... (again, PERSONALITY section, scroll down bestie)
• I_WANT_A_BROKEN_PS — forces the obsolete command line interpretation. yes that is literally the name. iconic, unhinged, we love her 💀
• LC_TIME — controls the date format. the vibe of your timestamps, essentially ✨
• LIBPROC_HIDE_KERNEL — set this to any value to hide kernel threads, which are normally shown with the -e option. this is equivalent to selecting --ppid 2 -p 2 --deselect instead. also works in BSD mode. sneak mode activated 🙈
• PS_COLORS — not currently supported. rip to a real one, we miss her 😭
• PS_FORMAT — default output format override. you can set this to a format string of the type used for the -o option. the DefSysV and DefBSD values are particularly useful. highly recommend, ate 🔥
• POSIXLY_CORRECT — don't find excuses to ignore bad "features". (yes the scare quotes are doing a LOT of work there, and yes they're in the original, i'm just the messenger 💅)
• POSIX2 — when set to "on", acts as POSIXLY_CORRECT.
• UNIX95 — don't find excuses to ignore bad "features".
• _XPG — cancels the CMD_ENV=irix non-standard behavior.

in general, it is a bad idea to set these variables. like, please don't, bestie. 🙏

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. and we don't stan useless and bad parts, periodt 💖

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🎀 PERSONALITY 🎀

pick your fighter:

• 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 — * recommended * 👑 (this is the one, choose this one)
• old — like the original Linux ps (totally non-standard)
• os390 — like OS/390 Open Edition ps
• 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)
• svr4 — standard
• sysv — standard
• tru64 — like Tru64 (was Digital Unix, was OSF/1) ps
• unix — standard
• unix95 — standard
• unix98 — standard

the range?? the versatility?? she contains multitudes 🌈

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💀 BUGS 💀

okay so listen, not everything is perfect, and we have to be honest about it:

• the fields bsdstart and start will only show the abbreviated month name in English. soz to everyone else 🥲
• the fields lstart and stime will show the abbreviated month name in the configured locale, but may exceed the column width — because abbreviated month and day names have different lengths across languages. so your columns might get a little... chaotic. it's giving "formatting? never heard of her" 😭

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🦋 SEE ALSO 🦋

go read these next, bestie, they're all bangers:

pgrep(1), pstree(1), top(1), strftime(3), proc(5), capabilities(7).

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⭐ STANDARDS ⭐

this ps conforms to the following standards. she's certified, she's accredited, she has papers 📜✨

• Version 2 of the Single Unix Specification
• The Open Group Technical Standard Base Specifications, Issue 6
• IEEE Std 1003.1, 2004 Edition
• X/Open System Interfaces Extension [UP XSI]
• ISO/IEC 9945:2003

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💖 AUTHOR 💖

ps was originally written by Branko Lankester. Michael K. Johnson re-wrote it significantly to use the proc filesystem, changing a few things in the process. Michael Shields added the pid-list feature. Charles Blake 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 rewrote ps for full Unix98 and BSD support, along with some ugly hacks for obsolete and foreign syntax.

look at this lineup. legends only. the way they all just kept adding features?? main character energy, all of them 👑

please send bug reports to procps@freelists.org. No subscription is required or suggested. just show up and say what's wrong, we're all friends here 🫶

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aaaand that's a wrap on ps(1), bestie!! 🎀 this one's from the procps-ng crew and the page is dated 2025-04-23 — so it's giving fresh, it's giving current, it's giving "yes we actually maintain this." go forth and ps aux responsibly, you absolute icon 💅✨🌸