Linux下PS命令详解
整理自：http://blog.chinaunix.net/space.php?uid=20564848&do=blog&id=74654
要对系统中进程进行监测控制，查看状态，内存，CPU的使用情况，使用命令：/bin/ps
（1） ps ：是显示瞬间进程的状态，并不动态连续；
（2） top：如果想对进程运行时间监控，应该用 top 命令；
（3） kill 用于杀死进程或者给进程发送信号；
（4） 查看文章最后的man手册，可以查看ps的每项输出的含义，to find: STANDARD FORMAT SPECIFIERS
===================================ps 的参数说明=============================
l 长格式输出；
u 按用户名和启动时间的顺序来显示进程；
j 用任务格式来显示进程；
f 用树形格式来显示进程；
a 显示所有用户的所有进程（包括其它用户）；
x 显示无控制终端的进程；
r 显示运行中的进程；
ww 避免详细参数被截断；
-A 列出所有的进程
-w 显示加宽可以显示较多的资讯
-au 显示较详细的资讯
-aux 显示所有包含其他使用者的进程
-e 显示所有进程,环境变量
-f 全格式
-h 不显示标题
-l 长格式
-w 宽输出
a 显示终端上地所有进程,包括其他用户地进程
r 只显示正在运行地进程
x 显示没有控制终端地进程
我们常用的选项是组合是 aux 或 lax，还有参数 f 的应用。
pids 只列出进程标识符,之间运用逗号分隔.该进程列表必须在命令行参数地最后一个选项后面紧接着给出,中间不能插入空格.比如：ps -f1,4,5 显示的是进程ID为1,4,5的进程
下介绍长命令行选项,这些选项都运用“--”开头：
--sort X[+|-] key [,[+|-] key [,…]] 从SORT KEYS段中选一个多字母键.“+”字符是可选地,因为默认地方向就是按数字升序或者词典顺序，“-”字符是逆序排序（即降序）.
比如： ps -jax
-sort=uid,-ppid,+pid.
--help 显示帮助信息.
--version 显示该命令地版本信息.
在前面地选项说明中提到了排序键,接下来对排序键作进一步说明.需要注意地是排序中运用地值是ps运用地内部值,并非仅用于某些输出格式地伪值.排序键列表见下表.
============排序键列表==========================
c cmd 可执行地简单名称
C cmdline 完整命令行
f flags 长模式标志
g pgrp 进程地组ID
G tpgid 控制tty进程组ID
j cutime 累计用户时间
J cstime 累计系统时间
k utime 用户时间
K stime 系统时间
m min_flt 次要页错误地数量
M maj_flt 重点页错误地数量
n cmin_flt 累计次要页错误
N cmaj_flt 累计重点页错误
o session 对话ID
p pid 进程ID
P ppid 父进程ID
r rss 驻留大小
R resident 驻留页
s size 内存大小(千字节)
S share 共享页地数量
t tty tty次要设备号
T start_time 进程启动地时间
U uid UID
u user 用户名
v vsize 总地虚拟内存数量(字节)
y priority 内核调度优先级
========================================ps aux 或 lax 输出的解释=========================
2、ps aux 或 lax 输出的解释
au(x) 输出格式 :
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
USER: 进程所有者
PID: 进程ID
%CPU: 占用的 CPU 使用率
%MEM: 占用的内存使用率
VSZ: 占用的虚拟内存大小
RSS: 占用的内存大小
TTY: 终端的次要装置号码 (minor device number of tty)
STAT: 进程状态:
START: 启动进程的时间；
TIME: 进程消耗CPU的时间；
COMMAND:命令的名称和参数；
=========================================进程STAT状态==================================
D 无法中断的休眠状态（通常 IO 的进程）；
R 正在运行，在可中断队列中；
S 处于休眠状态，静止状态；
T 停止或被追踪，暂停执行；
W 进入内存交换（从内核2.6开始无效）；
X 死掉的进程；
Z 僵尸进程不存在但暂时无法消除；
W: 没有足够的记忆体分页可分配
WCHAN 正在等待的进程资源；
<: 高优先级进程
N: 低优先序进程
L: 有记忆体分页分配并锁在记忆体内 (即时系统或捱A
I/O)，即,有些页被锁进内存
s 进程的领导者（在它之下有子进程）；
l 多进程的（使用 CLONE_THREAD, 类似 NPTL
pthreads）；
+ 位于后台的进程组；
========================================kill 终止进程================================
kill 终止进程
有十几种控制进程的方法，下面是一些常用的方法:
kill -STOP [pid]
发送SIGSTOP
(17,19,23)停止一个进程，而并不消灭这个进程。
kill -CONT [pid]
发送SIGCONT
(19,18,25)重新开始一个停止的进程。
kill -KILL [pid]
发送SIGKILL (9)强迫进程立即停止，并且不实施清理操作。
kill -9 -1
终止你拥有的全部进程。
SIGKILL 和 SIGSTOP 信号不能被捕捉、封锁或者忽略，但是，其它的信号可以。所以这是你的终极武器。
==================================================范例==============================
$ ps
PID TTY TIME COMMAND
5800 ttyp0 00:00:00 bash
5835 ttyp0 00:00:00 ps
可以看到,显示地项目共分为四项,依次为PID(进程ID)、TTY(终端名称)、TIME(进程执行时
间)、COMMAND(该进程地命令行输入).
可以运用u选项来查看进程所有者及其他少许详细信息,如下所示：
$ ps u
USER PID %CPU %MEM USZ RSS TTY STAT START TIME COMMAND
test 5800 0.0 0.4 1892 1040 ttyp0 S Nov27 0:00 -bash
test 5836 0.0 0.3 2528 856 ttyp0 R Nov27 0:00 ps u
在bash进程前面有条横线,意味着该进程便是用户地登录shell,所以对于一个登录用户来说带短横线地进程只有一个.还可以看 到%CPU、%MEM两个选项,前者指该进程占用地CPU时间
和总时间地百分比;后者指该进程占用地内存和总内存地百分比.
在这种情况下看到了所有控制终端地进程;当然对于其他那些没有控制终端地进程 还是没有观察到,所以这时就需要运用x选项.运用x选项可以观察到所有地进程情况.
1)ps a 显示现行终端机下的所有程序，包括其他用户的程序。
2)ps -A 显示所有程序。
3)ps c 列出程序时，显示每个程序真正的指令名称，而不包含路径，参数或常驻服务的标示。
4)ps -e 此参数的效果和指定"A"参数相同。
5)ps e 列出程序时，显示每个程序所使用的环境变量。
6)ps f 用ASCII字符显示树状结构，表达程序间的相互关系。
7)ps -H 显示树状结构，表示程序间的相互关系。
8)ps -N 显示所有的程序，除了执行ps指令终端机下的程序之外。
9)ps s 采用程序信号的格式显示程序状况。
10)ps S 列出程序时，包括已中断的子程序资料。
11)ps -t<终端机编号> 指定终端机编号，并列出属于该终端机的程序的状况。
12)ps u 以用户为主的格式来显示程序状况。
13)ps x 显示所有程序，不以终端机来区分。
最常用的方法是ps -aux,然后再用管道符号导向到grep去查找特定的进程,然后再对特定的进程进行操作。
==================================================
luther@gliethttp:~$ ps --help
********* simple selection ********* ********* selection by list
*********
-A all
processes
-C by command name
-N negate
selection
-G by real group ID (supports names)
-a all w/ tty except session leaders -U by real user ID (supports names)
-d all except session leaders
-g by session OR by effective group name
-e all
processes
-p by process ID
T all processes on this terminal -s processes in
the sessions given
a all w/ tty, including other users -t by tty
g OBSOLETE -- DO NOT
USE -u
by effective user ID (supports names)
r only running
processes
U processes for specified users
x processes w/o controlling ttys t by tty
*********** output format ********** *********** long options ***********
-o,o user-defined -f
full --Group
--User --pid --cols --ppid
-j,j job control s
signal --group --user
--sid --rows --info
-O,O preloaded -o v virtual memory --cumulative --format
--deselect
-l,l long u
user-oriented --sort --tty --forest --version
-F extra full X
registers --heading --no-heading --context
********* misc options *********
-V,V show version L list format
codes f ASCII art forest
-m,m,-L,-T,H threads S children in
sum -y change -l format
-M,Z security data c true command
name -c scheduling class
-w,w wide output n numeric
WCHAN,UID -H process hierarchy
luther@gliethttp:~$ man ps
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 -eopid,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 -p 42 -o comm=
SIMPLE PROCESS SELECTION
-A Select all processes. Identical to -e.
-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.
-a Select all processes except both session leaders (see
getsid(2)) and processes not associated with a
terminal.
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.
-d Select all processes except session leaders.
-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.
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
-C cmdlist Select by command name.
This selects the processes whose executable name is
given in cmdlist.
-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).
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).
-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.
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.
-s sesslist Select by session ID.
This selects the processes with a session ID specified
in sesslist.
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.
-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.
--Group grplist Select by real group ID (RGID) or name. Identical to
-G.
--User userlist Select by real user ID (RUID) or name. Identical to -U.
--group grplist Select by effective group ID (EGID) or name.
This selects the processes whose effective group name
or ID is in grouplist. The effective group ID describes
the group whose file access permissions are used by the
process (see geteuid(2)). The -g option is often an
alternative to --group.
--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.
--sid sesslist Select by session ID. Identical to -s.
--tty ttylist Select by terminal. Identical to -t and t.
--user userlist Select by effective user ID (EUID) or name. Identical
to -u and U.
-123
Identical to --sid 123.
123
Identical to --pid 123.
OUTPUT FORMAT CONTROL
These options are used to choose the information displayed by ps. The
output may differ by personality.
-F
extra full format. See the -f option, which -F implies.
-O format is 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 is preloaded o (overloaded).
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). When used as a formatting option,
it is identical to -O, with the BSD personality.
-M
Add a column of security data. Identical to Z.
(for SE Linux)
X
Register format.
Z
Add a column of security data. Identical to -M.
(for SE Linux)
-c
Show different scheduler information for the -l option.
-f
does full-format listing. This option can be combined
with many other UNIX-style options to add additional
columns. It also causes the command arguments to be
printed. When used with -L, the NLWP (number of
threads) and LWP (thread ID) columns will be added. See
the c option, the format keyword args, and the format
keyword comm.
j
BSD job control format.
-j
jobs format
l
display BSD long format.
-l
long format. The -y option is often useful with this.
o format specify user-defined format.
Identical to -o and
--format.
-o format user-defined format.
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) as desired.
If all column headers are empty (ps -o pid= -o comm=)
then the header line will not be output. Column width
will increase as needed for wide headers; this may be
used 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.
s
display signal format
u
display user-oriented format
v
display virtual memory format
-y
Do not show flags; show rss in place of addr. This
option can only be used with -l.
--format format user-defined format. Identical to -o and o.
--context Display security context format.
(for SE Linux)
OUTPUT MODIFIERS
-H
show process hierarchy (forest)
N namelist Specify namelist file. Identical to
-n, see -n above.
O order Sorting order.
(overloaded)
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, 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 may help to distinguish
an O sort from an O format. The "-" reverses direction
only on the key it precedes.
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.
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 is
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.
e
Show the environment after the command.
f
ASCII-art process hierarchy (forest)
h
No header. (or, one header per screen in the BSD
personality)
The h option is 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.
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 default direction is increasing
numerical or lexicographic order. Identical to --sort.
Examples:
ps jaxkuid,-ppid,+pid
ps axk comm o comm,args
ps kstart_time -ef
-n namelist set namelist file. Identical to N.
The namelist file is needed for a proper WCHAN display,
and must match the current Linux kernel exactly for
correct output. Without this option, the default search
path for the namelist is:
$PS_SYSMAP
$PS_SYSTEM_MAP
/proc/*/wchan
/boot/System.map-`uname -r`
/boot/System.map
/lib/modules/`uname -r`/System.map
/usr/src/linux/System.map
/System.map
n
Numeric output for WCHAN and USER. (including all types
of UID and GID)
-w
Wide output. Use this option twice for unlimited width.
w
Wide output. Use this option twice for unlimited width.
--cols n set screen width
--columns n set screen width
--cumulative include some dead child process data (as a sum
with the
parent)
--forest ASCII art process tree
--headers repeat header lines, one per page
of output
--no-headers print no header line at all. --no-heading is an
alias
for this option.
--lines n set screen height
--rows n set screen height
--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 default direction is increasing
numerical or lexicographic order. Identical to k. For
example: ps jax --sort=uid,-ppid,+pid
--width n set screen width
THREAD DISPLAY
H
Show threads as if they were processes
-L
Show threads, possibly with LWP and NLWP columns
-T
Show threads, possibly with SPID column
m
Show threads after processes
-m
Show threads after processes
OTHER INFORMATION
L
List all format specifiers.
-V
Print the procps version.
V
Print the procps version.
--help Print a help
message.
--info Print debugging
info.
--version Print the procps version.
NOTES
This ps works by reading the virtual files
in /proc. This ps does not
need to be setuid kmem or have any
privileges to run. Do not give this
ps any special permissions.
This ps needs access to namelist data for
proper WCHAN display. For
kernels prior to 2.6, the System.map file
must be installed.
CPU usage is currently expressed as the percentage
of time spent
running during the entire lifetime of a
process. This is not ideal,
and it does not conform to the standards
that ps otherwise conforms to.
CPU usage is unlikely to add up to exactly
100%.
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
that remain because their parent has not
destroyed them properly. These
processes will be destroyed by init(8) if
the parent process exits.
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
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 IO)
R Running or runnable
(on run queue)
S Interruptible sleep
(waiting for an event to complete)
T Stopped, either by a
job control signal or because it is being
traced.
W paging (not valid
since the 2.6.xx kernel)
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 IO)
s is a session leader
l is multi-threaded
(using CLONE_THREAD, like NPTL pthreads do)
+ is in the foreground
process group
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.
KEY
LONG DESCRIPTION
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 kilobytes
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 kB
y
priority kernel scheduling priority
AIX FORMAT DESCRIPTORS
This ps supports AIX format descriptors,
which work somewhat like the
formatting codes of printf(1) and
printf(3). For example, the normal
default output can be produced with
this: ps -eo "%p %y %x %c".
The NORMAL
codes are described in the next section.
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
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.
CODE HEADER
DESCRIPTION
%cpu
%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
%MEM ratio of the process's resident set size to the physical
memory on the machine, expressed as a percentage.
(alias pmem).
args
COMMANDcommand with all its arguments as a string. Modifications
to the arguments may be shown. The output in this column
may contain spaces. A process marked
dead, waiting to be fully destroyed by its parent.
Sometimes the process args will be unavailable; when this
happens, ps will instead print 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 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 or --cols 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 BLOCKEDmask of the
blocked signals, see signal(7). According to
the width of the field, a 32-bit or 64-bit mask in
hexadecimal format is displayed.
(alias sig_block, sigmask).
bsdstart 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 dd" (where mmm is the three letters of the month).
See also lstart, start, start_time, and stime.
bsdtime 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 C
processor utilization. Currently, this is the integer
value of the percent usage over the lifetime of the
process. (see %cpu).
caught 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.
(alias sig_catch, sigcatch).
class
CLS scheduling class of the process. (alias policy, cls).
Field's possible values are:
- not reported
TS SCHED_OTHER
FF SCHED_FIFO
RR SCHED_RR
B SCHED_BATCH
ISO SCHED_ISO
IDL SCHED_IDLE
? unknown value
cls
CLS scheduling class of the process. (alias policy, class).
Field's possible values are:
- not reported
TS SCHED_OTHER
FF SCHED_FIFO
RR SCHED_RR
B SCHED_BATCH
ISO SCHED_ISO
IDL SCHED_IDLE
? unknown value
cmd
CMD see args. (alias args, command).
comm
COMMANDcommand name (only the executable name). Modifications to
the command name will not be shown. A process marked
its parent. The output in this column may contain spaces.
(alias ucmd, ucomm). See also the args 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 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 or --cols 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.
command COMMANDsee args.
(alias args, cmd).
cp
CP per-mill (tenths of a percent) CPU usage. (see
%cpu).
cputime TIME
cumulative CPU time, "[dd-]hh:mm:ss" format. (alias time).
egid
EGID effective group ID number of the process as a decimal
integer. (alias gid).
egroup EGROUP effective
group ID of the process. This will be the
textual group ID, if it can be obtained and the field
width permits, or a decimal representation otherwise.
(alias group).
eip
EIP instruction pointer.
esp
ESP stack pointer.
etime
ELAPSEDelapsed time since the process was started, in the
form [[dd-]hh:]mm:ss.
euid
EUID effective user ID. (alias uid).
euser EUSER
effective user name. This will be the textual user ID,
if it can be obtained and the field width permits,
or a decimal representation otherwise. The n option can be
used to force the decimal representation.
(alias uname, user).
f
F flags associated with the process, see the
PROCESS FLAGS
section. (alias flag, flags).
fgid
FGID filesystem access group ID. (alias fsgid).
fgroup FGROUP filesystem
access group ID. This will be the textual
user ID, if it can be obtained and the field width
permits, or a decimal representation otherwise.
(alias fsgroup).
flag
F see f. (alias f, flags).
flags
F see f. (alias f, flag).
fname COMMANDfirst
8 bytes of the base name of the process's executable
file. The output in this column may contain spaces.
fuid
FUID filesystem access user ID. (alias fsuid).
fuser FUSER
filesystem access user ID. This will be the textual
user ID, if it can be obtained and the field width
permits, or a decimal representation otherwise.
gid
GID see egid. (alias egid).
group GROUP
see egroup. (alias egroup).
ignored IGNOREDmask of the
ignored signals, see signal(7). According to
the width of the field, a 32-bit or 64-bit mask in
hexadecimal format is displayed. (alias sig_ignore,
sigignore).
label LABEL
security label, most commonly used for SE Linux context
data. This is for the Mandatory Access Control ("MAC")
found on high-security systems.
lstart STARTEDtime the
command started. See also bsdstart, start,
start_time, and stime.
lwp
LWP lwp (light weight process, or thread) ID of the lwp being
reported. (alias spid, tid).
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).
nlwp
NLWP number of lwps (threads) in the process. (alias thcount).
nwchan WCHAN
address of the kernel function where the process is
sleeping (use wchan if you want the kernel function name).
Running tasks will display a dash ('-') in this column.
pcpu
%CPU see %cpu. (alias %cpu).
pending PENDINGmask of the
pending signals. See signal(7). Signals
pending on the process are distinct from signals pending
on individual threads. Use the m option or the -m option
to see both. According to the width of the field, a 32-bit
or 64-bit mask in hexadecimal format is displayed.
(alias sig).
pgid
PGID process group ID or, equivalently, the process ID of the
process group leader. (alias pgrp).
pgrp
PGRP see pgid. (alias pgid).
pid
PID process ID number of the process.
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
? unknown value
ppid
PPID parent process ID.
pri
PRI priority of the process. Higher number means lower
priority
psr
PSR processor that process is currently assigned to.
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.
rss
RSS resident set size, the non-swapped physical memory that a
task has used (in kiloBytes). (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, and SCHED_IDLE are respectively displayed as
0, 1, 2, 3, 4, and 5.
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
PENDINGsee pending. (alias pending, sig_pend).
sigcatch CAUGHT see caught. (alias
caught, sig_catch).
sigignore IGNOREDsee ignored. (alias
ignored, sig_ignore).
sigmask BLOCKEDsee blocked.
(alias blocked, sig_block).
size
SZ approximate amount of swap space that would be
required if
the process were to dirty all writable pages and then be
swapped out. This number is very rough!
spid
SPID see lwp. (alias lwp, tid).
stackp STACKP address of
the bottom (start) of stack for the process.
start STARTEDtime
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 lstart, bsdstart, start_time, and stime.
start_timeSTART 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).
suid
SUID saved user ID. (alias svuid).
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.
thcount THCNT see nlwp.
(alias nlwp). number of kernel threads owned by
the process.
tid
TID see lwp. (alias lwp).
time
TIME cumulative CPU time, "[dd-]hh:mm:ss" format.
(alias cputime).
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.
tt TT
controlling tty (terminal). (alias tname, tty).
tty
TT controlling tty (terminal). (alias tname, tt).
ucmd CMD
see comm. (alias comm, ucomm).
ucomm COMMANDsee
comm. (alias comm, ucmd).
uid
UID see euid. (alias euid).
uname
USER see euser. (alias euser, user).
user
USER see euser. (alias euser, uname).
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).
wchan WCHAN
name of the kernel function in which the process is
sleeping, a "-" if the process is running, or a "*" if the
process is multi-threaded and ps is not displaying
threads.
ENVIRONMENT VARIABLES
The following environment variables could
affect ps:
COLUMNS
Override default display
width.
LINES
Override default display
height.
PS_PERSONALITY
Set to one of posix,
old, linux, bsd, sun, digital...
(see section PERSONALITY
below).
CMD_ENV
Set to one of posix,
old, linux, bsd, sun, digital...
(see section PERSONALITY
below).
I_WANT_A_BROKEN_PS
Force obsolete command
line interpretation.
LC_TIME
Date format.
PS_COLORS
Not currently supported.
PS_FORMAT
Default output format
override. You may set this to a format string
of the type used for the
-o option. The DefSysV and DefBSD values
are particularly useful.
PS_SYSMAP
Default namelist
(System.map) location.
PS_SYSTEM_MAP
Default namelist
(System.map) location.
POSIXLY_CORRECT
Don't find excuses to
ignore bad "features".
POSIX2
When set to
"on", acts as POSIXLY_CORRECT.
UNIX95
Don't find excuses to
ignore bad "features".
_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
390 like the S/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 *****
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
SEE ALSO
top(1), pgrep(1), pstree(1), proc(5).
STANDARDS
This ps conforms to:
1 Version 2 of the Single Unix
Specification
2 The Open Group Technical
Standard Base Specifications, Issue 6
3 IEEE Std 1003.1, 2004
Edition
4 X/Open System Interfaces
Extension [UP XSI]
5 ISO/IEC 9945:2003
AUTHOR
ps was originally written by Branko
Lankester
Michael K. Johnson
use the proc filesystem, changing a few
things in the process. Michael
Shields
Blake
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
Unix98 and BSD support, along with some
ugly hacks for obsolete and
foreign syntax.
Please send bug reports to
No subscription is required or suggested.
Linux
July 28,
2004
PS(1)