<a name=


Process status, information about processes running in memory. If you want a repetitive update of this status, use top.

      Display Process info
         ps option(s)

      List all the keyword options
         ps [-L]


     This version of ps accepts 3 kinds of option:

        * Unix98 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. The PS_PERSONALITY 
       environment variable provides more detailed control  of ps behavior.

       The Options below are listed side-by-side (unless there are differences).


       -A  a        select all processes (including those of other users)
       -a           select all with a tty except session leaders
       -d           select all, but omit session leaders
       -e           select all processes
       g            really all, even group leaders (does nothing w/o SunOS settings)       -N           negate selection
       r            restrict output to running processes
       T            select all processes on this terminal
       x            select processes without controlling ttys
       --deselect   negate selection


     -C              select by command name
     -G              select by RGID (supports names)
     -g              select by session leader OR by group name
            --Group  select by real group name or ID
            --group  select by effective group name or ID
     -p  p  --pid    select by process ID (PID)
     -s     --sid    select by session ID
     -t     --tty    select by terminal (tty)
     -u  U           select by effective user ID (supports names)
     -U              select by RUID (supports names)
            --User   select by real user name or ID
            --user   select by effective user name or ID

     -123      implied --sid
     123       implied --pid


       -c         Different scheduler info for -l option
       -f         Full listing
       -j  j      Jobs format
       -l  l      Long format
       -O  O      Add the information associated with the space or comma separated
	          list of keywords specified, after the process ID, in the default
	          information display.
       -o  o      Display information associated with the space or comma separated
	          list of keywords specified.
       --format   user-defined format
        s         display signal format
        u         display user-oriented format
        v         display virtual memory format
        X         old Linux i386 register format
       -y         do not show flags; show rss in place of addr

       C              use raw CPU time for %CPU instead of decaying average
       c              true command name
       e              show environment after the command
       f              ASCII-art process hierarchy (forest)
       -H             show process hierarchy (forest)
       h              do not print header lines (repeat header lines in BSD personality)
       -m  m          show all threads
       -n             set namelist file
       n              numeric output for WCHAN and USER
       N              specify namelist file
       O              sorting order (overloaded)
       S              include some dead child process data (as a  sum  with the parent)
       -w  w          wide output
       --cols         set screen width
       --columns      set screen width
       --forest       ASCII art process tree
       --html         HTML escaped output
       --headers      repeat header lines
       --no-headers   print no header line at all
       --lines        set screen height
       --nul          unjustified output with NULs
       --null         unjustified output with NULs
       --rows         set screen height
       --sort         specify sorting order
       --width        set screen width
       --zero         unjustified output with NULs

       -V  V       print version
       L           list all format specifiers
       --help      print help message
       --info      print debugging info
       --version   print version

       A        increase the argument space (DecUnix)
       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)

       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 varies between BSD personality and Linux usage
       (not printing  the  header) Regardless of the current personality,
       you can use the long options --headers and --no-headers
       Terminals (ttys, or screens of text output) can be  specified in several forms: /dev/ttyS1, ttyS1, S1.
       Obsolete "ps t" (your own terminal) and "ps t?" (processes without a terminal)
       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
       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, specify the other option (sorting or
       formatting) 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

       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:
              /boot/System.map-`uname -r`
              /lib/modules/`uname -r`/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

       Programs swapped out to disk will be shown without command
       line  arguments,  and  unless  the  c  option is given, in

       %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   are dead processes (so-called
       "zombies")  that  remain  because  their  parent  has  not
       destroyed them properly. These processes will be destroyed
       by init(8) if the parent process exits.

       ALIGNWARN    001   print alignment warning msgs
       STARTING     002   being created
       EXITING      004   getting shut down
       PTRACED      010   set if ptrace (0) has been called
       TRACESYS     020   tracing system calls
       FORKNOEXEC   040   forked but didn't exec
       SUPERPRIV    100   used super-user privileges
       DUMPCORE     200   dumped core
       SIGNALED     400   killed by a signal

       D   uninterruptible sleep (usually 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:
       W   has no resident pages
       <   high-priority process
       N   low-priority task
       L   has pages locked into memory (for real-time and custom IO)



       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=

Since ps cannot run faster than the system and is run as any other scheduled process, the information it displays can never be exact.

Related commands:

top - List running processes on the system