top.1

linux下获取一些环境信息的代码

.ig
. manual page for NEW top
. Copyright (c) 2002, by:      JC Warner & Associates, Ltd.
.
. Permission is granted to copy, distribute and/or modify this document
. under the terms of the GNU Free Documentation License, Version 1.1 or
. any later version published by the Free Software Foundation;
. with no Front-Cover Texts, no Back-Cover Texts, and with the following
. Invariant Sections (and any sub-sections therein):
.   all .ig sections, including this one
.   STUPID TRICKS Sampler
.   AUTHOR
.
. A copy of the Free Documentation License is included in the section
. entitled "GNU Free Documentation License".
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. [ that section is found near the end of this document & ]
. [ can be made printable by disabling the .ig directive! ]
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..
.\" Setup ////////////////////////////////////////////////////////////////
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\#                      Commonly used strings (for consistency) ----------
\#                          - a real em-dash, darn-it
.ds EM \ \fB\-\-\ \fR
\#                          - these two are for chuckles, makes great grammar
.ds Me top
.ds ME \fBtop\fR
\#                          - other misc strings for consistent usage/emphasis
.ds F \fIOff\fR
.ds O \fIOn\fR
.
.ds AM alternate\-display mode
.ds AS asterisk ('*')
.ds CF configuration file
.ds CI interactive command
.ds CO command\-line option
.ds CW \'current' window
.ds FM full\-screen mode
.ds MP \fBphysical\fR memory
.ds MS \fBshared\fR memory
.ds MV \fBvirtual\fR memory
.ds NT \fBNote\fR:
.ds PU CPU
.ds Pu cpu
.ds SA summary area
.ds TA task area
.ds TD task display
.ds TW task window
\#                          - xref's that depend on commands or topic names
.ds XC See the
.ds Xc see the
.ds XT See topic
.ds Xt see topic
.
.\" //////////////////////////////////////////////////////////////////////
.\" ----------------------------------------------------------------------
.TH TOP 1 "September 2002" "Linux" "Linux User's Manual"
.\" ----------------------------------------------------------------------


.\" ----------------------------------------------------------------------
.SH NAME
.\" ----------------------------------------------------------------------
top \- display Linux tasks


.\" ----------------------------------------------------------------------
.SH SYNOPSIS
.\" ----------------------------------------------------------------------
\*(ME \-\fBhv\fR | \-\fBbcHisS\fR \-\fBd\fI delay\fR \-\fBn\fI
iterations\fR \-\fBp\fI pid\fR [,\fI pid\fR ...]

The traditional switches '-' and whitespace are optional.


.\" ----------------------------------------------------------------------
.SH DESCRIPTION
.\" ----------------------------------------------------------------------
The \*(ME program provides a dynamic real-time view of a running system.
It can display\fB system\fR summary information as well as a list of\fB
tasks\fR currently being managed by the Linux kernel.
The types of system summary information shown and the types, order and
size of information displayed for tasks are all user configurable and
that configuration can be made persistent across restarts.

The program provides a limited interactive interface for process
manipulation as well as a much more extensive interface for personal
configuration \*(EM encompassing every aspect of its operation.
And while \*(ME is referred to throughout this document, you are free
to name the program anything you wish.
That new name, possibly an alias, will then be reflected on \*(Me's display
and used when reading and writing a \*(CF.


.\" ----------------------------------------------------------------------
.SH OVERVIEW
.\" ----------------------------------------------------------------------
.\" ......................................................................
.SS Documentation
.\" ----------------------------------------------------------------------
The remaining Table of Contents
    1. COMMAND\-LINE Options
    2. FIELDS / Columns
       a. DESCRIPTIONS of Fields
       b. SELECTING and ORDERING Columns
    3. INTERACTIVE Commands
       a. GLOBAL Commands
       b. SUMMARY Area Commands
       c. TASK Area Commands
       d. COLOR Mapping
    4. ALTERNATE\-DISPLAY Mode
       a. WINDOWS Overview
       b. COMMANDS for Windows
    5. FILES
       a. SYSTEM Configuration File
       b. PERSONAL Configuration File
    6. STUPID TRICKS Sampler
       a. Kernel Magic
       b. Bouncing Windows
       c. The Big Bird Window
    7. BUGS, 8. HISTORY Former top, 9. AUTHOR, 10. SEE ALSO

.\" ......................................................................
.SS Operation
.\" ----------------------------------------------------------------------
When operating \*(Me, the two most important keys are help ('h' or '?') and
quit ('q') key.
Alternatively, you could simply use the traditional interrupt key ('^C')
when you're done.

When you start \*(Me for the first time, you'll be presented with the
traditional screen elements: 1) Summary Area; 2) Message/Prompt Line;
3) Columns Header; 4) Task Area.
There will, however, be some differences when compared to the former top.

.TP 3
.B Highlighting
.I Summary_Area\fR:
There is no highlighting for load/uptime and only values are highlighted for
other elements.

.I Task_Area\fR:
Tasks running (or ready to run) will be highlighted, and bold is only one way
of emphasizing such processes.

.TP 3
.B Content/Labels
.I Summary_Area\fR:
The program name is shown, perhaps a symlink or alias.
The Cpu(s) state label hints at other possibilities.
The memory stats use a lower case 'k'.

.I Columns_Header\fR:
Will show a new field and some changed labels.
More new fields will be found as you customize your \*(Me.

.PP
\*(NT the width of \*(Me's display will be limited to 512 positions.
Displaying all fields requires a minimum of 160 characters.
The remaining width could be used for the 'Command' column.

.\" ......................................................................
.SS Startup Defaults
.\" ----------------------------------------------------------------------
The following startup defaults assume no \*(CF, thus no user customizations.
Even so, items shown with an \*(AS could be overridden through the
command-line.

    \fIGlobal_defaults\fR
       'A' - Alt display      Off (full-screen)
     * 'd' - Delay time       3.0 seconds
       'I' - Irix mode        On\ \ (no, 'solaris' smp)
     * 'p' - PID monitoring   Off
     * 's' - Secure mode      Off (unsecured)
       'B' - Bold disable     Off
    \fISummary_Area_defaults\fR
       'l' - Load Avg/Uptime  On\ \ (thus program name)
       't' - Task/Cpu states  On\ \ (1+1 lines, see '1')
       'm' - Mem/Swap usage   On\ \ (2 lines worth)
       '1' - Single Cpu       On\ \ (thus 1 line if smp)
    \fITask_Area_defaults\fR
       'b' - Bold hilite      On\ \ (not 'reverse')
     * 'c' - Command line     Off (name, not cmdline)
     * 'H' - Threads          Off\ (show all threads)
     * 'i' - Idle tasks       On\ \ (show all tasks)
       'R' - Reverse sort     On\ \ (pids high-to-low)
     * 'S' - Cumulative time  Off (no, dead children)
       'x' - Column hilite    Off\ (no, sort field)
       'y' - Row hilite       On\ \ (yes, running tasks)
       'z' - color/mono       Off\ (no, colors)


.\" ----------------------------------------------------------------------
.SH 1. COMMAND-LINE Options
.\" ----------------------------------------------------------------------
The command-line syntax for \*(Me consists of:

     \-\fBhv\fR\ |\ -\fBbcHisS\fR\ \-\fBd\fI\ delay\fR\ \-\fBn\fI\ iterations\
\fR\ \-\fBp\fI\ pid\fR\ [,\fIpid\fR...]

The typically mandatory switches ('-') and even whitespace are completely
optional.

.TP 5
\-\fBb\fR :\fB Batch mode\fR operation
Starts \*(Me in 'Batch mode', which could be useful for sending output
from \*(Me to other programs or to a file.
In this mode, \*(Me will not accept input and runs until the iterations
limit you've set with the '-n' \*(CO or until killed.

.TP 5
\-\fBc\fR :\fB Command line/Program name\fR toggle
Starts \*(Me with the last remembered 'c' state reversed.
Thus, if \*(Me was displaying command lines, now that field will show program
names, and visa versa.
\*(XC 'c' \*(CI for additional information.

.TP 5
\-\fBd\fR :\fB Delay time\fR interval as:\ \ \fB-d ss.tt\fR (\fIseconds\fR.\fItenths\fR)
Specifies the delay between screen updates, and overrides the corresponding
value in one's personal \*(CF or the startup default.
Later this can be changed with the 'd' or 's' \*(CIs.

Fractional seconds are honored, but a negative number is not allowed.
In all cases, however, such changes are prohibited if \*(Me is running
in 'Secure mode', except for root (unless the 's' \*(CO was used).
For additional information on 'Secure mode' \*(Xt 5a. SYSTEM Configuration File.


.TP 5
\-\fBh\fR :\fB Help\fR
Show library version and the usage prompt, then quit.

.TP 5
\-\fBH\fR :\fB Threads\fR toggle
Starts \*(Me with the last remembered 'H' state reversed.
When this toggle is \*O, all individual threads will be displayed.  Otherwise, \*(Me displays a summation of all threads in a process.

.TP 5
\-\fBi\fR :\fB Idle Processes\fR toggle
Starts \*(Me with the last remembered 'i' state reversed.
When this toggle is \*F, tasks that are idled or zombied will not be displayed.

.TP 5
\-\fBn\fR :\fB Number of iterations\fR limit as:\fB\ \ -n number\fR
Specifies the maximum number of iterations, or frames, \*(Me should
produce before ending.

.TP 5
\-\fBu\fR :\fB Monitor by user\fR as:\fB\ \ -u somebody
Monitor only processes with an effective UID or user name
matching that given.

.TP 5
\-\fBU\fR :\fB Monitor by user\fR as:\fB\ \ -U somebody
Monitor only processes with a UID or user name matching that given.
This matches real, effective, saved, and filesystem UIDs.

.TP 5
\-\fBp\fR :\fB Monitor PIDs\fR as:\fB\ \ -pN1 -pN2 ...\fR\ \ or\fB\ \ -pN1, N2 [,...]
Monitor only processes with specified process IDs.
This option can be given up to 20 times, or you can provide a comma delimited
list with up to 20 pids.
Co-mingling both approaches is permitted.

This is a \*(CO only.
And should you wish to return to normal operation, it is not necessary
to quit and and restart \*(Me \*(EM just issue the '=' \*(CI.

.TP 5
\-\fBs\fR :\fB Secure mode\fR operation
Starts \*(Me with secure mode forced, even for root.
This mode is far better controlled through the system \*(CF
(\*(Xt 5. FILES).

.TP 5
\-\fBS\fR :\fB Cumulative time mode\fR toggle
Starts \*(Me with the last remembered 'S' state reversed.
When 'Cumulative mode' is \*O, each process is listed with the \*(Pu
time that it and its dead children have used.
\*(XC 'S' \*(CI for additional information regarding this mode.

.TP 5
\-\fBv\fR :\fB Version\fR
Show library version and the usage prompt, then quit.


.\" ----------------------------------------------------------------------
.SH 2. FIELDS / Columns
.\" ----------------------------------------------------------------------
.\" ......................................................................
.SS 2a. DESCRIPTIONS of Fields
.\" ----------------------------------------------------------------------
Listed below are \*(Me's available fields.
They are always associated with the letter shown, regardless of the position
you may have established for them with the 'o' (Order fields) \*(CI.

Any field is selectable as the sort field, and you control whether they
are sorted high-to-low or low-to-high.
For additional information on sort provisions \*(Xt 3c. TASK Area Commands.

.TP 3
a:\fB PID\fR \*(EM Process Id\fR
The task's unique process ID, which periodically wraps,
though never restarting at zero.