PS(S) Linux User's Manual PS(S) NAME ps - report process status SYNOPSIS ps [options] DESCRIPTION ps gives a snapshot of the current processes. If you want a repetitive update of this status, use top. This man page documents the /proc-based version of ps, or tries to. OPTIONS This version of ps accepts several kinds of options. Unix options may be grouped and must be preceeded by a dash. BSD options may be grouped and must not be used with a dash. GNU long options are preceeded by two dashes. Options of different types may be freely mixed. Set the I_WANT_A_BROKEN_PS environment variable to force BSD syntax even when options are preceeded by a dash. The PS_PERSONALITY environment variable (described below) pro- vides more detailed control of ps behavior. SIMPLE PROCESS SELECTION lfB l. -A select all processes -N negate selection -a select all with a tty except session leaders -d select all, but omit session leaders -e select all processes T select all processes on this terminal a select all processes on a terminal, including those of other users g really all, even group leaders (does nothing w/o SunOS settings) r restrict output to running processes x select processes without controlling ttys --deselect negate selection PROCESS SELECTION BY LIST lfB l. -C select by command name -G select by RGID (supports names) -U select by RUID (supports names) -g select by session leader OR by group name -p select by PID -s select processes belonging to the sessions given -t select by tty -u select by effective user ID (supports names) U select processes for specified users p select by process ID t select by tty --Group select by real group name or ID --User select by real user name or ID --group select by effective group name or ID --pid select by process ID --sid select by session ID --tty select by terminal --user select by effec- tive user name or ID -123 implied --sid 123 implied --pid OUTPUT FORMAT CONTROL lfB l. -O is preloaded "-o" -c different scheduler info for -l option -f does full listing -j jobs format -l long format -o user- defined format -y do not show flags; show rss in place of addr O is preloaded "o" (overloaded) X old Linux i386 register format j job control format l Display long format o specify user-defined format s display signal format u display user-oriented format v dis- play virtual memory format --format user-defined format OUTPUT MODIFIERS lfB l. -H show process hierarchy (for- est) -m shows threads -n sets namelist file -w wide output C use raw CPU time for %CPU instead of decaying average N specify namelist file O sorting order (overloaded) S, --cumulative include some dead child process data (as a sum with the parent) c true command name e show environment after the command f, --for- est ASCII-art process hierarchy (forest) h no header (or, one header per screen in the BSD personality) m all threads n numeric output for WCHAN and USER --cols, --columns, --width set screen width --head- ers repeat header lines, one per page of output --no-head- ers print no header line at all --lines, --rows set screen height --sort specify sorting order INFORMATION lfB l. -V, V, --version print version L list all format specifiers --help print help mes- sage --info print debugging info OBSOLETE lfB l. A increases the argument space (DecU- nix) M use alternate core (try -n or N instead) W get swap info from ... not /dev/drum (try -n or N instead) k use /vmcore as c-dumpfile (try -n or N instead) NOTES The -g option can select by session leader OR by group name. Selection by session leader is specified by many standards, but selection by group is the logical behavior that several other operating systems use. This ps will select by session leader when the list is completely numeric (as sessions are). Group ID numbers will work only when some group names are also specified. The m option should not be used. Use -m or -o with a list. (m displays memory info, shows threads, or sorts by memory use) The h option is problematic. Standard BSD ps uses the option to print a header on each page of output, but older Linux ps uses the 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 and disable headers entirely, respec- tively. Terminals (ttys, or screens for text output) can be speci- fied in several forms: /dev/ttyS1, ttyS1, S1. Obsolete ps t (your own terminal) and ps t? (processes without a ter- minal) syntax is supported, but modern options (T, -t with list, x, t with list) should be used instead. The BSD O option can act like -O (user-defined output for- mat 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 behav- ior is obtained, specify the other option (sorting or for- matting) in some other way. For sorting, BSD O option syntax is O[+|-]k1[,[+|-]k2[,...]] Order the process listing according to the multilevel sort specified by the sequence of short keys from SORT KEYS, k1, k2, ... The `+' is quite optional, merely re-iterating the default direction on a key. `-' reverses direction only on the key it precedes. The O option must be the last option in a single command argument, but specifications in successive arguments are catenated. GNU sorting syntax is --sortX[+|-]key[,[+|-]key[,...]] Choose a multi-letter key from the SORT KEYS section. X may be any convenient separator character. To be GNU-ish use `='. The `+' is really optional since default direc- tion is increasing numerical or lexicographic order. For example, ps jax --sort=uid,-ppid,+pid This ps works by reading the virtual files in /proc. This ps does not need to be suid kmem or have any privileges to run. Do not give this ps any special permissions. This ps needs access to a namelist file for proper WCHAN display. The namelist file must match the current Linux kernel exactly for correct output. To produce the WCHAN field, ps needs to read the Sys- tem.map file created when the kernel is compiled. The search path is: $PS_SYSTEM_MAP /boot/System.map-`uname -r` /boot/System.map /lib/modules/`uname -r`/System.map /usr/src/linux/System.map The member used_math of task_struct is not shown, since crt0.s checks to see if math is present. This causes the math flag to be set for all processes, and so it is worth- less. (Somebody fix libc or the kernel please) Programs swapped out to disk will be shown without command line arguments, and unless the c option is given, in brackets. %CPU shows the cputime/realtime percentage. It will not add up to 100% unless you are lucky. It is time used divided by the time the process has been running. The SIZE and RSS fields don't count the page tables and the task_struct of a proc; this is at least 12k of memory that is always resident. SIZE is the virtual size of the proc (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(t) if the parent process exits. PROCESS FLAGS l l l. ALIGNWARN 001 print alignment warn- ing msgs STARTING 002 being created EXITING 004 get- ting shut down PTRACED 010 set if ptrace (0) has been called TRACESYS 020 tracing system calls FORK- NOEXEC 040 forked but didn't exec SUPERPRIV 100 used super-user privileges DUMPCORE 200 dumped core SIGNALED 400 killed by a signal PROCESS STATE CODES l l. D uninterruptible sleep (usu- ally IO) R runnable (on run queue) S sleeping T traced or stopped Z a defunct ("zombie") process For BSD formats and when the "stat" keyword is used, addi- tional letters may be displayed: l l. W has no resi- dent pages < high-priority process N low-priority task L has pages locked into memory (for real-time and custom IO) SORT KEYS Note that the values used in sorting are the internal val- ues ps uses and not the `cooked' values used in some of the output format fields. Pipe ps output into the sort(t) command if you want to sort the cooked values. l l l. KEY LONG DESCRIPTION c cmd simple name of executable C cmdline full command line 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 K stime 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 o ses- sion session ID p pid process ID P ppid parent process ID r rss resident set size R resident res- ident pages s size memory size in kilobytes S share amount of shared pages t tty the minor device number of tty T start_time time process was started U uid user ID number u user user name v vsize total VM size in kB y priority kernel scheduling priority AIX FORMAT DESCRIPTORS This ps supports AIX format descriptors, which work some- what like the formatting codes of printf(f) and printf(f). For example, the normal default output can be produced with this: ps -eo "%p %y %x %c" l l l. CODE NORMAL HEADER %C pcpu %CPU %G group GROUP %P ppid PPID %U user USER %a args COMMAND %c comm COMMAND %g rgroup RGROUP %n nice NI %p pid PID %r pgid PGID %t etime ELAPSED %u ruser RUSER %x time TIME %y tty TTY %z vsz VSZ STANDARD FORMAT SPECIFIERS These may be used to control both output format and sort- ing. For example: ps -eo pid,user,args --sort user l l. CODE HEADER %cpu %CPU %mem %MEM alarm ALARM args COMMAND blocked BLOCKED bsdstart START bsd- time TIME c C caught CAUGHT cmd CMD comm COMMAND command COMMAND cputime TIME drs DRS dsiz DSIZ egid EGID egroup EGROUP eip EIP esp ESP etime ELAPSED euid EUID euser EUSER f F fgid FGID fgroup FGROUP flag F flags F fname COMMAND fsgid FSGID fsgroup FSGROUP fsuid FSUID fsuser FSUSER fuid FUID fuser FUSER gid GID group GROUP ignored IGNORED intpri PRI lim LIM longtname TTY lstart STARTED m_drs DRS m_trs TRS maj_flt MAJFL majflt MAJFLT min_flt MINFL minflt MINFLT ni NI nice NI nwchan WCHAN opri PRI pagein PAGEIN pcpu %CPU pend- ing PENDING pgid PGID pgrp PGRP pid PID pmem %MEM ppid PPID pri PRI priority PRI rgid RGID rgroup RGROUP rss RSS rssize RSS rsz RSZ ruid RUID ruser RUSER s S sess SESS session SESS sgi_p P sgi_rss RSS sgid SGID sgroup SGROUP sid SID sig PENDING sig_block BLOCKED sig_catch CATCHED sig_ignore IGNORED sig_pend SIGNAL sigcatch CAUGHT sigignore IGNORED sigmask BLOCKED stackp STACKP start STARTED start_stack STACKP start_time START stat STAT state S stime STIME suid SUID suser SUSER svgid SVGID svgroup SVGROUP svuid SVUID svuser SVUSER sz SZ time TIME timeout TMOUT tmout TMOUT tname TTY tpgid TPGID trs TRS trss TRSS tsiz TSIZ tt TT tty TT tty4 TTY tty8 TTY ucmd CMD ucomm COMMAND uid UID uid_hack UID uname USER user USER vsize VSZ vsz VSZ wchan WCHAN ENVIRONMENT VARIABLES The following environment variables could affect ps: lfB l. COLUMNS Override default display width. LINES Override default display height. PS_PERSONAL- ITY Set to one of posix,old,linux,bsd,sun,digital... CMD_ENV Set to one of posix,old,linux,bsd,sun,digital... I_WANT_A_BROKEN_PS Force obsolete command line interpre- tation. LC_TIME Date format. PS_COLORS Not currently supported. PS_FORMAT Default output format override. PS_SYSMAP Default namelist (System.map) location. PS_SYS- TEM_MAP Default namelist (System.map) location. POSIXLY_CORRECT Don't find excuses to ignore bad "fea- tures". UNIX95 Don't find excuses to ignore bad "fea- tures". _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 l l. 390 like the S/390 OpenEdition ps aix like AIX ps bsd like FreeBSD ps (totally non-stan- dard) compaq like Digital Unix ps debian like the old Debian ps digital like Digital Unix ps gnu like the old Debian ps hp like HP-UX ps hpux like HP-UX ps irix like Irix ps linux ***** RECOMMENDED ***** old like the original Linux ps (totally non-standard) posix standard sco like SCO ps sgi like Irix ps sun like SunOS 4 ps (totally non-standard) sunos like SunOS 4 ps (totally non-standard) sysv standard unix stan- dard unix95 standard unix98 standard EXAMPLES To see every process on the system using standard syntax: ps -e To see every process on the system using BSD syntax: ps ax To see every process except those running as root (real & effective ID) ps -U root -u root -N To see every process with a user-defined format: ps -eo pid,tt,user,fname,tmout,f,wchan Odd display with AIX field descriptors: ps -o "%u : %U : %p : %a" Print only the process IDs of syslogd: ps -C syslogd -o pid= CONFORMING TO This ps conforms to version 2 of the Single Unix Specifi- cation. AUTHOR ps was originally written by Branko Lankester <lankeste@fwi.uva.nl>. Michael K. Johnson <johnsonm@red- hat.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 fea- ture. Charles Blake <cblake@bbn.com> added multi-level sorting, the dirent-style library, the device name-to-num- ber mmaped database, the approximate binary search directly on System.map, and many code and documentation cleanups. David Mossberger-Tang wrote the generic BFD sup- port for psupdate. Albert Cahalan <acahalan@cs.uml.edu> rewrote ps for full Unix98 and BSD support, along with some ugly hacks for obsolete and foreign syntax. Please send bug reports to <acahalan@cs.uml.edu> or use the Debian Bug Tracking System. SEE ALSO top(p), pstree(e), proc(c) Linux July 5, 1998 PS(S)