ps命令
ps 命令是一个非常强大的工具，用于显示当前系统中的进程状态。
基本概念
ps 是 “process status” 的缩写，它可以列出运行中的进程信息，比如进程 ID（PID）、用户、CPU 和内存使用情况、命令名称等。
man ps（查看ps帮助信息）
DESCRIPTION
[root@vgt-rocky9-60 ~]# man ps >1
[root@vgt-rocky9-60 ~]# cat 1
PS(1) User Commands PS(1)
NAME
ps - report a snapshot of the current
processes. ### 报告当前进程快照状态
SYNOPSIS
ps [options]
DESCRIPTION
ps displays information about a selection of the active processes. If you want a repetitive update of the selection
and the displayed information, use top instead.
This version of ps accepts several kinds of options:
1 UNIX options, which may be grouped and must be preceded by a dash. ### unix选项, 选项前一个破折号 -
2 BSD options, which may be grouped and must not be used with a dash. ### unix选项, 选项前不能有破折号
3 GNU long options, which are preceded by two dashes. ### unix选项, 选项前两个破折号 --
Options of different types may be freely mixed, but conflicts can appear. There are some synonymous options, which
are functionally identical, due to the many standards and ps implementations that this ps is compatible with.
Note that ps -aux is distinct from ps aux. The POSIX and UNIX standards require that ps -aux print all processes
owned by a user named x, as well as printing all processes that would be selected by the -a option. If the user
named x does not exist, this ps may interpret the command as ps aux instead and print a warning. This behavior is
intended to aid in transitioning old scripts and habits. It is fragile, subject to change, and thus should not be
relied upon.
By default, ps selects all processes with the same effective user ID (euid=EUID) as the current user and associated
with the same terminal as the invoker. It displays the process ID (pid=PID), the terminal associated with the
process (tname=TTY), the cumulated CPU time in [DD-]hh:mm:ss format (time=TIME), and the executable name (ucmd=CMD).
Output is unsorted by default.
The use of BSD-style options will add process state (stat=STAT) to the default display and show the command args
(args=COMMAND) instead of the executable name. You can override this with the PS_FORMAT environment variable. The
use of BSD-style options will also change the process selection to include processes on other terminals (TTYs) that
are owned by you; alternately, this may be described as setting the selection to be the set of all processes
filtered to exclude processes owned by other users or not on a terminal. These effects are not considered when
options are described as being "identical" below, so -M will be considered identical to Z and so on.
Except as described below, process selection options are additive. The default selection is discarded, and then the
selected processes are added to the set of processes to be displayed. A process will thus be shown if it meets any
of the given selection criteria.
PS EXAMPLES
EXAMPLES
To see every process on the system using standard unix 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 ### 显示进程树
To get info about threads:
ps -eLf
ps axms
To get security info: ### selinux label
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 -Ao pid,tt,user,fname,tmout,f,wchan
Print only the process IDs of syslogd:
ps -C syslogd -o pid= ### 输出关联进程pid
Print only the name of PID 42:
ps -q 42 -o comm=
SIMPLE PROCESS SELECTION
SIMPLE PROCESS SELECTION
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.
-A Select all processes. Identical to -e.
-a Select all processes except both session leaders (see getsid(2)) and processes not associated with a
terminal.
-d Select all processes except session leaders.
--deselect
Select all processes except those that fulfill the specified conditions (negates the selection). Identical
to -N.
-e Select all processes. Identical to -A. ### 所有进程
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.
-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.
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
-123 Identical to --pid 123.
123 Identical to --pid 123.
-C cmdlist
Select by command name. This selects the processes whose executable name is given in cmdlist. NOTE: The
command name is not the same as the command line. Previous versions of procps and the kernel truncated this
command name to 15 characters. This limitation is no longer present in both. If you depended on matching only
15 characters, you may no longer get a match.
-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).
-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.
--Group grplist
Select by real group ID (RGID) or name. Identical to -G.
--group grplist
Select by effective group ID (EGID) or name. This selects the processes whose effective group name or ID is
in grplist. The effective group ID describes the group whose file access permissions are used by the process
(see getegid(2)). The -g option is often an alternative to --group.
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.
--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.
q pidlist
Select by process ID (quick mode). Identical to -q and --quick-pid.
-q pidlist
Select by PID (quick mode). This selects the processes whose process ID numbers appear in pidlist. With
this option ps reads the necessary info only for the pids listed in the pidlist and doesn't apply additional
filtering rules. The order of pids is unsorted and preserved. No additional selection options, sorting and
forest type listings are allowed in this mode. Identical to q and --quick-pid.
--quick-pid pidlist
Select by process ID (quick mode). Identical to -q and q.
-s sesslist
Select by session ID. This selects the processes with a session ID specified in sesslist.
--sid sesslist
Select by session ID. Identical to -s.
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.
--tty ttylist
Select by terminal. Identical to -t and t.
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).
-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.
--User userlist
Select by real user ID (RUID) or name. Identical to -U.
--user userlist
Select by effective user ID (EUID) or name. Identical to -u and U.
OUTPUT FORMAT CONTROL
These options are used to choose the information displayed by ps. The output may differ by personality.
-c Show different scheduler information for the -l option.
--context
Display security context format (for SELinux).
-f Do 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.
-F Extra full format. See the -f option, which -F implies.
--format format
user-defined format. Identical to -o and o.
j BSD job control format.
-j Jobs format.
l Display BSD long format.
-l Long format. The -y option is often useful with this.
-M Add a column of security data. Identical to Z (for SELinux).
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.
-O format
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
Specify user-defined format. Identical to -o and --format.
-o format ### 格式化输出
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.
X Register format.
-y Do not show flags; show rss in place of addr. This option can only be used with -l.
Z Add a column of security data. Identical to -M (for SELinux).
OUTPUT MODIFIERS
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.
--cols n
Set screen width.
--columns n
Set screen width.
--cumulative
Include some dead child process data (as a sum with the parent).
e Show the environment after the command.
f ASCII art process hierarchy (forest).
--forest
ASCII art process tree.
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.
-H Show process hierarchy (forest).
--headers
Repeat header lines, one per page of output.
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
--lines n
Set screen height.
n Numeric output for WCHAN and USER (including all types of UID and GID).
--no-headers
Print no header line at all. --no-heading is an alias for this option.
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.
--rows n
Set screen height.
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.
--sort spec ### 排序
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
w Wide output. Use this option twice for unlimited width.
-w Wide output. Use this option twice for unlimited width.
--width n
Set screen width.
THREAD DISPLAY
H Show threads as if they were processes.
-L Show threads, possibly with LWP and NLWP columns.
m Show threads after processes.
-m Show threads after processes.
-T Show threads, possibly with SPID column.
OTHER INFORMATION
--help section
Print a help message. The section argument can be one of simple, list, output, threads, misc, or all. The
argument can be shortened to one of the underlined letters as in: s|l|o|t|m|a.
--info Print debugging info.
L List all format specifiers.
V Print the procps-ng version.
-V Print the procps-ng version.
--version
Print the procps-ng 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.
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 <defunct> 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.
If the length of the username is greater than the length of the display column, the username will be truncated. See
the -o and -O formatting options to customize length.
Commands options such as ps -aux are not recommended as it is a confusion of two different standards. According to
the POSIX and UNIX standards, the above command asks to display all processes with a TTY (generally the commands
users are running) plus all processes owned by a user named x. If that user doesn't exist, then ps will assume you
really meant ps aux.
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（状态码）
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)
I Idle kernel thread ### 空闲内核线程
R running or runnable (on run queue)
S interruptible sleep (waiting for an event to complete)
T stopped by job control signal
t stopped by debugger during the tracing
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（排序key）
1 | OBSOLETE SORT KEYS |
常用命令组合
ps -ef //输出所有进程
ps axjf //显示进程树
ps -eo pid,tid,class,rtprio,ni,pri,psr,pcpu,stat,wchan:14,comm //格式化输出列
ps h -eo pid,ni,comm
ps -C sshd -o pid= //输出关联进程pid
ps -q 42 -o comm= //输出pid对应的command
ps -h //no header
ps -ef --sort=-ppid,+pid //排序输出 +升序 -降序
ps aux --sort=-%cpu //进程cpu占用降序
ps aux --sort=-%cpu |head
ps输出nice及调整进程nice值
在 Linux 中，ps 命令可以用来查看进程信息，包括进程的 nice 值（调度优先级）。Nice 值表示进程的优先级，范围从 -20（最高优先级）到 19（最低优先级），默认值为 0。
要查看进程的 nice 值，可以在 ps 命令中使用适当的选项。以下是一个常用的示例：
1 | ps -eo pid,ni,comm |
解释：
-e：显示所有进程。-o：自定义输出格式。pid：进程 ID。ni：Nice 值。comm：命令名（进程名称）。
示例输出：
PID NI COMMAND
1 0 systemd
2 0 kthreadd
123 10 myprogram
在这个例子中：
PID是进程的 ID。NI是 nice 值，比如10表示该进程的优先级较低。COMMAND是进程对应的命令或程序名。
如果你想要更详细的信息：
可以用以下命令查看更多字段：
1 | ps -aux |
在这里，NI 列也会显示 nice 值（通常在第 8 列）。例如：
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
root 1 0.0 0.1 123456 7890 ? Ss Feb24 0:01 /sbin/init
user 123 0.0 0.2 456789 12345 pts/0 S 10:00 0:00 myprogram
NI 列默认不显示，但可以通过调整 ps 的输出格式（比如用 -o）明确包含。
调整 Nice 值：
如果需要修改某个进程的 nice 值，可以使用 renice 命令。例如：
1 | //syntax |
这会将 PID 为 123 的进程的 nice 值设置为 10。