ps.1

linux下获取一些环境信息的代码

executable file, rather than from the argv value. Command arguments
and any modifications to them (see\ \fIsetproctitle\fR(3)) are
thus not shown. This option
effectively turns the \fBargs\fR format keyword into the \fBcomm\fR
format keyword; it is useful with the \fB\-f\fR format option and with
the various BSD\-style format options, which all normally
display the command arguments.
See the \fB\-f\fR option, the format keyword \fBargs\fR, and the
format keyword \fBcomm\fR.

.opt e
Show the environment after the command.

.opt f
ASCII\-art process hierarchy (forest)

.opt h
No header. (or, one header per screen in the BSD personality)
.br
The \fBh\fR option is problematic.  Standard BSD \fBps\fR uses
this option to print a header on each page of output, but older
Linux \fBps\fR uses this option to totally disable the header.
This version of \fBps\fR 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 \fB\-\-headers\fR
and \fB\-\-no\-headers\fR to enable printing headers each page or
disable headers entirely, respectively.

.opt k \ spec
specify sorting order. Sorting syntax is
[\fB+\fR|\fB\-\fR]\fIkey\fR[,[\fB+\fR|\fB\-\fR]\fIkey\fR[,...]]
Choose a multi\-letter key from the \fBSTANDARD FORMAT SPECIFIERS\fR section.
The\ "+" is optional since default direction is increasing numerical or
lexicographic order. Identical to \fB\-\-sort\fR. Examples:
.br
\fBps\ jaxkuid,\-ppid,+pid\fR
.br
\fBps\ axk\ comm\ o\ comm,args\fR
.br
\fBps\ kstart_time\ \-ef\fR

.opt \-n \ namelist
set namelist file.  Identical to \fBN\fR.
.br
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
.br
	$PS_SYSTEM_MAP
.br
	/proc/*/wchan
.br
	/boot/System.map\-\`uname\ \-r\`
.br
	/boot/System.map
.br
	/lib/modules/\`uname\ \-r\`/System.map
.br
	/usr/src/linux/System.map
.br
	/System.map

.opt n
Numeric output for WCHAN and USER. (including all types of UID and GID)

.opt \-w
Wide output. Use this option twice for unlimited width.

.opt w
Wide output. Use this option twice for unlimited width.

.opt \-\-cols \ n
set screen width

.opt \-\-columns \ n
set screen width

.opt \-\-cumulative
include some dead child process data (as a sum with the parent)

.opt \-\-forest
ASCII art process tree

.opt \-\-headers
repeat header lines, one per page of output

.opt \-\-no\-headers
print no header line at all

.opt \-\-lines \ n
set screen height

.opt \-\-rows \ n
set screen height

.opt \-\-sort \ spec
specify sorting order. Sorting syntax is
[\fB+\fR|\fB\-\fR]\fIkey\fR[,[\fB+\fR|\fB\-\fR]\fIkey\fR[,...]]
Choose a multi\-letter key from the \fBSTANDARD FORMAT SPECIFIERS\fR section.
The\ "+" is optional since default direction is increasing numerical or
lexicographic order. Identical to\ \fBk\fR.
For example: \fBps\ jax\ \-\-sort=uid,\-ppid,+pid\fR

.opt \-\-width \ n
set screen width

.\" """""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
.PD
.PP
.SH "THREAD DISPLAY"
.PD 0

.opt H
Show threads as if they were processes

.opt \-L
Show threads, possibly with LWP and NLWP columns

.opt \-T
Show threads, possibly with SPID column

.opt m
Show threads after processes

.opt \-m
Show threads after processes

.\" """""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
.PD
.PP
.SH "OTHER INFORMATION"
.PD 0

.opt L
List all format specifiers.

.opt \-V
Print the procps version.

.opt V
Print the procps version.

.opt \-\-help
Print a help message.

.opt \-\-info
Print debugging info.

.opt \-\-version
Print the procps version.

.\" """""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
.PD
.PP
.SH NOTES
This \fBps\fR works by reading the virtual files in\ /proc.
This \fBps\fR does not need to be setuid kmem or have any privileges to run.
Do not give this \fBps\fR any special permissions.

This \fBps\fR 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 \fBps\fR 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 \fIinit\fR(8) if the parent process exits.


.SH "PROCESS FLAGS"
The sum of these values is displayed in the "F" column,
which is provided by the \fBflags\fR output specifier.
.PD 0
.TP 5
1
forked but didn't exec
.TP
4
used super\-user privileges
.PD
.PP
.SH "PROCESS STATE CODES"
Here are the different values that the \fBs\fR, \fBstat\fR and
\fBstate\fR output specifiers (header\ "STAT"\ or\ "S") will display to
describe the state of a process.
.PD 0
.TP 5
D
Uninterruptible sleep (usually\ IO)
.TP
R
Running or runnable (on\ run\ queue)
.TP
S
Interruptible sleep (waiting for an event to complete)
.TP
T
Stopped, either by a job control signal or because it is being traced.
.TP
W
paging (not valid since the 2.6.xx kernel)
.TP
X
dead (should never be seen)
.TP
Z
Defunct ("zombie") process, terminated but not reaped by its parent.
.PD
.PP
For BSD formats and when the \fBstat\fR keyword is used, additional
characters may be displayed:
.PD 0
.TP 5
<
high\-priority (not nice to other users)
.TP
N
low\-priority (nice to other users)
.TP
L
has pages locked into memory (for real\-time and custom\ IO)
.TP
s
is a session leader
.TP
l
is multi-threaded (using CLONE_THREAD, like NPTL pthreads\ do)
.TP
+
is in the foreground process group
.PD
.PP
.PP
.SH "OBSOLETE SORT KEYS"
These keys are used by the BSD \fBO\fR option (when it is used for
sorting).  The GNU \fB\-\-sort\fR option doesn't use these keys, but the
specifiers described below in the \fBSTANDARD FORMAT SPECIFIERS\fR
section. Note that the values used in sorting are the internal
values \fBps\fR 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 \fBps\fR output into the \fIsort\fR(1) command if you want
to sort the cooked values.

.TS
l l lw(3i).
\fBKEY	LONG	DESCRIPTION\fR
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
.\"K	stime	system time (conflict, system vs. start time)
.TE
.PP
.PP
.SH "AIX FORMAT DESCRIPTORS"
This \fBps\fR supports AIX format descriptors, which work somewhat like the
formatting codes of \fIprintf\fR(1) and \fIprintf\fR(3). For example, the normal
default output can be produced with this:  \fBps\ \-eo\ "%p\ %y\ %x\ %c"\fR.
The\ \fBNORMAL\fR codes are described in the next section.
.TS
l l l.
\fBCODE	NORMAL	HEADER\fR
%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
.TE

.SH "STANDARD FORMAT SPECIFIERS"
Here are the different keywords that may be used to control the output
format (e.g. with option \fB\-o\fR) or to sort the selected processes
with the GNU\-style \fB\-\-sort\fR option.

For example:  \fBps\ \-eo\ pid,user,args\ \-\-sort\ user\fR

This version of \fBps\fR tries to recognize most of the keywords used in
other implementations of \fBps\fR.

The following user\-defined format specifiers may contain
spaces: \fBargs\fR, \fBcmd\fR, \fBcomm\fR, \fBcommand\fR, \fBfname\fR,
\fBucmd\fR, \fBucomm\fR,
\fBlstart\fR, \fBbsdstart\fR, \fBstart\fR.

Some keywords may not be available for sorting.

.\" #######################################################################
.\" lB1 lB1 lB1 lB1 s s s
.\" lB1 l1  l1  l1  s s s.
.\"
.\" lB1 lB1 lBw(5.5i)
.\" lB1 l1  l.
.\"
.TS
expand;
lB1 lB1 lBw(\n[ColSize]n)
lB1 l1  l.
CODE	HEADER	DESCRIPTION

%cpu	%CPU	T{
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\ \fBpcpu\fR).
T}

%mem	%MEM	T{
ratio of the process's resident set size  to the physical memory on
the machine, expressed as a percentage.  (alias\ \fBpmem\fR).
T}

args	COMMAND	T{
command 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 <defunct> is partly dead, waiting
to be fully destroyed by its parent. Sometimes the process args
will be unavailable; when this happens, \fBps\fR will instead
print the executable name in brackets.
(alias\ \fBcmd\fR,\ \fBcommand\fR). See also the \fBcomm\fR format
keyword, the \fB\-f\fR option, and the \fBc\fR option.
.br
When specified last, this column will extend to the edge of the display.
If \fBps\fR 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 \fBTERM\fR variable, and so on)
The \fBCOLUMNS\fR environment variable or \fB\-\-cols\fR option may
be used to exactly determine the width in this case.
The \fBw\fR or \fB\-w\fR option may be also be used to adjust width.
T}

blocked	BLOCKED	T{
mask of the blocked signals, see \fIsignal\fR(7).
According to the width of the field,
a\ 32\-bit or 64\-bit mask in hexadecimal format is displayed.
(alias\ \fBsig_block\fR,\ \fBsigmask\fR).
T}

bsdstart	START	T{
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).
T}

bsdtime	TIME	T{
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.
T}

c	C	T{
processor utilization. Currently, this is the integer value of
the percent usage over the lifetime of the process.  (see\ \fB%cpu\fR).
T}

caught	CAUGHT	T{
mask of the caught signals, see \fIsignal\fR(7).  According to the
width of the field, a 32 or 64 bits mask in hexadecimal format is
displayed.  (alias\ \fBsig_catch\fR,\ \fBsigcatch\fR).
T}

class	CLS	T{
scheduling class of the process.  (alias\ \fBpolicy\fR,\ \fBcls\fR).
Field's possible values are:
.br
\-	not reported
.br
TS	SCHED_OTHER
.br
FF	SCHED_FIFO
.br
RR	SCHED_RR
.br
?	unknown value
T}

cls	CLS	T{
scheduling class of the process.  (alias\ \fBpolicy\fR,\ \fBclass\fR).
Field's possible values are:
.br
\-	not reported
.br
TS	SCHED_OTHER
.br
FF	SCHED_FIFO
.br
RR	SCHED_RR
.br
?	unknown value
T}

cmd	CMD	T{
see \fBargs\fR.  (alias\ \fBargs\fR,\ \fBcommand\fR).
T}

comm	COMMAND	T{
command name (only\ the executable\ name).  Modifications to the command
name will not be shown. A\ process marked <defunct> is partly dead, waiting
to be fully destroyed by its parent. The output in this
column may contain spaces.  (alias\ \fBucmd\fR,\ \fBucomm\fR).
See also the \fBargs\fR format
keyword, the \fB\-f\fR option, and the \fBc\fR option.
.br
When specified last, this column will extend to the edge of the display.
If \fBps\fR 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 \fBTERM\fR variable, and so on)
The \fBCOLUMNS\fR environment variable or \fB\-\-cols\fR option may
be used to exactly determine the width in this case.
The \fBw\fR or \fB\-w\fR option may be also be used to adjust width.
T}

command	COMMAND	T{
see \fBargs\fR.  (alias\ \fBargs\fR,\ \fBcmd\fR).
T}

cp	CP	T{
per\-mill (tenths of a percent) CPU usage.  (see\ \fB%cpu\fR).
T}

cputime	TIME	T{
cumulative CPU time, "[dd\-]hh:mm:ss" format.  (alias\ \fBtime\fR).
T}

egid	EGID	T{
effective group ID number of the process as a decimal integer.
(alias\ \fBgid\fR).
T}

egroup	EGROUP	T{
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\ \fBgroup\fR).
T}

eip	EIP	T{
instruction pointer.
T}

esp	ESP	T{
stack pointer.
T}

etime	ELAPSED	T{
elapsed time since the process was started,
in\ the form\ [[dd\-]hh:]mm:ss.
T}

euid	EUID	T{
effective user\ ID. (alias\ \fBuid\fR).
T}

euser	EUSER	T{
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.