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ps - report process status
ps [-] [lujsvmaxScewhrnu] [txx] [O[+|-]k1[[+|-]k2...]]
[pids] there are also three long options:
More long options are on the way...
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.
- COMMAND-LINE OPTIONS
The command-line options for this version of ps are derived from the
BSD version of ps, not the System V version. The command-line arguments
should not be preceded by a `-' character, because in the future,
a `-' will be used to indicate Unix98-standard command-line arguments,
while no `-' will indicate the current ``extended BSD'' style of command
For now, ps will give you a warning if you use a `-' for a short option,
but it will still work. If you have shell scripts which use BSD-style
arguments to ps, take heed of the warning and fix them, or else your
scripts will fail to function correctly at some point in the future.
If you want to turn off the warnings, set the I_WANT_A_BROKEN_PS
There are also some ``long options'' in GNU style; see below for those.
- long format
- user format: gives user name and start time
- jobs format: pgid sid
- signal format
- vm format
- displays memory info (combine with p flag to get number of pages).
- "forest" family tree format for command line
a show processes of other users too
- show processes without controlling terminal
- add child cpu time and page faults
- command name from task_struct
- show environment after command line and ` + '
- wide output: don't truncate command lines to fit on one line.
To be exact, every w that is specified will add another possible line
to the output. If the space isn't needed it isn't used. You may up
to 100 w's. h no header r running procs only n numeric output for
USER and WCHAN.
- only procs with controlling tty xx; for xx you may use either
the name of a device file under "/dev" or that name
with either tty or cu sliced off. This is the reverse heuristic that
ps uses to print out the abbreviated tty name in the TT field, e.g.
- Order the process listing
according to the multilevel sort specified by the sequence of short
keys from SORT KEYS, k1, k2, ... Default order specifications exist
for each of the various formats of ps. These are over-ridden by a
user specified ordering. The `+' is quite optional, merely re-iterating
the default direction on a key. `-' reverses direction only on the
key it precedes.
As with t and pids, the O option must be the last option in a single
command argument, but specifications in successive arguments are catenated.
- List only the specified processes; they are comma- delimited.
The list must be given immediately after the last option in a single
command-line argument, with no intervening space, e.g. ps -j1,4,5.
Lists specified in subsequent arguments are catenated, e.g. ps -l
1,2 3,4 5 6 will list all of the processes 1-6 in long format. If
pids are given, they are listed no matter what. If a tty is given
matching processes are listed no matter what. These two features override
the 'a' and 'x' flags.
- LONG COMMAND-LINE OPTIONS
These options are preceded by a double-hyphen.
- 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 direction is increasing numerical or lexicographic order.
ps -jax -sort=uid,-ppid,+pid
- Get a help message that summarizes the usage and gives a
list of supported sort keys. This list may be more up to date than
this man page.
- Display version and source of this program.
- SORT KEYS
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.
- SHORT LONG DESCRIPTION
- cmd simple name of executable
- cmdline full command line
- flags flags as in long format F field
- pgrp process group ID
- tpgid controlling tty process group ID
- cutime cumulative user time
- cstime cumulative system time
- utime user time
- stime system time
- min_flt number of minor page faults
- maj_flt number of major page faults
- cmin_flt cumulative minor page faults
- cmaj_flt cumulative major page faults
- session session ID
- pid process ID
- ppid parent process ID
- rss resident set size
- resident resident pages
- size memory size in kilobytes
- share amount of shared pages
- tty the minor device number of tty
- start_time time process was started
- uid user ID number
- user user name
- vsize total VM size in bytes
- priority kernel scheduling priority
- FIELD DESCRIPTIONS
- This is the counter field in the task struct. It is the time
in HZ of the process's possible timeslice.
- Standard unix nice value; a positive value means less cpu time.
- Virtual image size; size of text+data+stack.
- Resident set size; kilobytes of program in memory.
- Name of the kernel function where the process is sleeping,
with the `sys_' stripped from the function name. If /etc/psdatabase
does not exist, it is just a hex number instead.
- Information about the status of the process. The first field
is R for runnable, S for sleeping, D for uninterruptible sleep, T
for stopped or traced, or Z for a zombie process. The second field
contains W if the process has no resident pages. The third field is
N if the process has a positive nice value (NI field).
- Controlling tty.
- Number of major page faults (page faults that cause pages
to be read from disk, including pages read from the buffer cache).
- Text resident size.
- Kilobytes (or pages if -p is used) on swap device.
- Shared memory.
- This proc-based ps works by reading the files in the proc
filesystem, mounted on /proc. This ps does not need to be suid kmem
or have any privileges to run. Do not give this ps any special permissions.
You will need to update the /etc/psdatabase file by running /usr/sbin/psupdateto
get meaningful information from the WCHAN field. This should be done
every time you compile a new kernel. You should also run 'ps' as root
once and then any time the tty devices in the "/dev"
As of procps-1.00, ps/top read System.map directly if it is available.
The search path for kernel address-to-symbol resolution is:
- /boot/System.map-`uname -r`
- /boot/psdatabase-`uname -r`
- /lib/modules/`uname -r`/psdatabase
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 worthless.
Programs swapped out to disk will be shown without command line arguments,
and unless the c option is given, in parentheses.
%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).
To perform the device number to name mapping ps maintains a file called
"/etc/psdevtab" (updated whenever "/dev"
becomes newer and permissions allow update). If permissions do not
allow update, every invokation of ps requires a stat(2) of every file
in the "/dev" directory. If "/dev"
entries change often on your system, you should run ps as root often.
I may add a fallback file under $HOME under force of popular demand.
ps was originally written by Branko Lankester <firstname.lastname@example.org>.
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 <email@example.com> added the pid-list feature.
Charles Blake <firstname.lastname@example.org> 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 support for
psupdate. Michael K. Johnson <johnsonm@red- hat.com> is the current
Please send bug reports to <email@example.com>
joe@localhost $ ps
PID TTY STAT TIME COMMAND
3485 1 S 0:00 xterm -sb
3509 p1 S 0:00 -bash
16910 2 S 0:00 /sbin/mingetty tty2
17024 p4 S 0:00 -bash
17076 3 S 0:00 (mingetty)
17077 4 S 0:00 (mingetty)
17078 5 S 0:00 (mingetty)
17079 6 S 0:00 (mingetty)
17647 p4 R 0:00 ps
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