ps -- Command

Print process status
ps [-][adefglmnrtwx] [-c sys] [mem] [-ppid,pid,...,pid]

ps  prints  information  about  a  process  or processes.   It  prints  the
information in  fields, followed  by the  command name and  arguments.  The
fields include the following:

TTY     The controlling  terminal of  the command,  printed in  short form.
        For example, ``tty44:'' means /dev/tty44. A  dash means there is no
        controlling terminal.

PID     Process id; necessary to know when the process is to be killed.

GROUP   PID of the  group leader  of the process,  that is, the  shell that
        started up when the user logged in.

PPID    PID of the parent of the process; very often a shell.

UID     User id or name of the owner.

K       Size of the process, in kilobytes.

F       Process flag bits, as follows:

        PFCORE  00001 Process is in core
        PFLOCK  00002 Process is locked in core
        PFSWIO  00004 Swap I/O in progress
        PFSWAP  00010 Process is swapped out
        PFWAIT  00020 Process is stopped (not waited)
        PFSTOP  00040 Process is stopped (waited on)
        PFTRAC  00100 Process is being traced
        PFKERN  00200 Kernel process
        PFAUXM  00400 Auxiliary segments in memory
        PFDISP  01000 Dispatch at earliest convenience
        PFNDMP  02000 Command mode forbids dump
        PFWAKE  04000 Wakeup requested

S       State of the process, as follows:

        R   Ready to run (waiting for CPU time)
        S   Stopped for other reasons (I/O completion, pause, etc.)
        T   Being traced by another process
        W   Waiting for an existent child
        Z   Zombie (dead, but parent not waiting)

EVENT   The  condition  that   the  process  is   anticipating.   This  not
        applicable if the process is ready to run.  The following gives the
        legal symbolic  names  of events.   If  a driver  does not  support
        symbolic  event  names,  ps  prints  a  unique  hexadecimal  number
        instead:

        System Sleeps:
        bpwait    Wait for a buffer to become valid
        bufneed   Wait for a free buffer to become available
        bwrite    Wait for a buffer write to finish
        ioreq     An IO request is being processed
        pause     This process is in the pause() system call
        pipe data Wait for data to appear in a pipe
        pipe wx
        poll      Wake for polled event, poll timeout, or signal
        ptrace    Send a ptrace command to a traced child
        ptret     Wait for signal processing in a traced child to complete
        pwrite    Wait for a pipe to empty enough for a write
        swap      Wait for a process to get swapped in
        wait      Wait for a child to terminate
        waitq     Wait for more character queues to become available

        Driver Sleeps
        aha:ccb   AHA-154x driver is waiting for a SCSI command to complete
        nkbcmd
        nkbcmd...
        nkbcmd2
        nkbcmd2...nkb is waiting for a command to complete
        ptycd     Pseudoterminal driver is waiting for carrier
        ptyread   Pseudoterminal driver is waiting for a read
        ptywrite  Pseudoterminal driver is waiting for a write
        ttydrain  Line discipline is waiting for a tty to drain
        ttyiodrn  ioctl() asked line discipline to let tty output drain
        ttyoq     Line discipline is waiting for an output queue to drain
        ttywait   Line discipline is waiting for more data

CVAL SVAL IVAL RVAL
        Scheduling information; bigger is better.

UTIME   Time consumed while running in the program (in seconds).

STIME   Time consumed while running in the system (in seconds).

Normally, ps displays the TTY and PID fields of each active process started
on the caller's  terminal, as well as the command  name and arguments.  The
following flags alter this behavior.

-a   Display information about processes started from all terminals.

-c sys
     This option does nothing; it  is included to preserve the integrity of
     some shell scripts.

-d   Print information about status of loadable drivers.

-e   Same  as   -a.   This  is   included  for  compatibility   with  other
     implementation of ps.

-f   Blank  fields  have `-'  place-holders.   This enables  field-oriented
     commands like sort and awk to process the output.

-g   Print the group leader field GROUP if the l option is given.

-k mem
     The next  argument mem is  the memory image  (default, /dev/mem). Note
     that  this argument  currently does  nothing; it  is included  only to
     preserve old  shell scripts.  The COHERENT  implementation of ps reads
     information from  /dev/ps. This permits  ps to be  smaller and faster,
     helps to avoid ``ghosts,'' and to be atomic.

-l   Long format.  In addition to the  TTY and PID fields, prints the PPID,
     UID, K, F, S and EVENT fields.

-m   This option does nothing; it  is included to preserve the integrity of
     some shell scripts.

-n   Suppress the header line.

-ppid,pid,...,pid
     Print  information  for  each process  identifier  pid  in the  comma-
     separated list.

-r   Print  the real  size  of the  process,  which includes  the user  and
     auxiliary segments assigned  to the process.  Because the user segment
     (usually 1  kilobyte) is shared  by all processes owned  by that user,
     this may give a misleading total size for all the user's processes.

-t   Print elapsed CPU time fields UTIME and STIME.

-w   Wide format output; print 132 columns instead of 80.

-x   Display processes which do not have a controlling terminal.

Files

/dev/ps -- Device for a system driver
/dev/tty* -- List of terminal names

See Also

commands,
hmon,
kill,
mem,
ps [device driver],b>a>
<a href="manpage.php?page=size"><b>size,b>a>
<a href="manpage.php?page=wait.c"><b>waitb>a>

<i>Notesi>

Each process  can modify  or destroy its  command name and  arguments.  The
state of the system changes even as ps runs.

© 2012 by Stephen A. Ness