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linux下获取一些环境信息的代码

belonging to the selected user will be displayed. This option
matches on the effective UID.

.TP 7
\ \ \'\fBU\fR\' :\fIselect a user\fR
You will be prompted for a UID or username. Only processes
belonging to the selected user will be displayed. This option
matches on the real, effective, saved, and filesystem UID.

.TP 7
*\ \'\fBk\fR\' :\fIKill_a_task\fR
You will be prompted for a PID and then the signal to send.
The default signal, as reflected in the prompt, is SIGTERM.
However, you can send any signal, via number or name.

If you wish to abort the kill process, do one of the following
depending on your progress:
   1) at the pid prompt, just press <Enter>
   2) at the signal prompt, type 0

.TP 7
\ \ \'\fBq\fR\' :\fIQuit\fR

.TP 7
*\ \'\fBr\fR\' :\fIRenice_a_Task\fR
You will be prompted for a PID and then the value to nice it to.
Entering a positive value will cause a process to lose priority.
Conversely, a negative value will cause a process to be viewed more
favorably by the kernel.

.TP 7
\ \ \'\fBW\fR\' :\fIWrite_the_Configuration_File\fR
This will save all of your options and toggles plus the current
display mode and delay time.
By issuing this command just before quitting \*(Me, you will be able restart
later in exactly that same state.

.TP 7
\ \ \'\fBZ\fR\' :\fIChange_Color_Mapping
This key will take you to a separate screen where you can change the
colors for the \*(CW, or for all windows.
For details regarding this \*(CI \*(Xt 3d. COLOR Mapping.

.IP "*" 3
The commands shown with an \*(AS are not available in 'Secure mode',
nor will they be shown on the level-1 help screen.

.\" ......................................................................
.SS 3b. SUMMARY Area Commands
The \*(SA \*(CIs are\fB always available\fR in both \*(FM and \*(AM.
They affect the beginning lines of your display and will determine the position
of messages and prompts.

These commands always impact just the \*(CW/field group.
\*(XT 4. ALTERNATE\-DISPLAY Mode and the 'G' \*(CI for insight into
\*(CWs and field groups.

.TP 7
\ \ \'\fBl\fR\' :\fIToggle_Load_Average/Uptime\fR \*(EM On/Off
This is also the line containing the program name (possibly an alias) when
operating in \*(FM or the \*(CW name when operating in \*(AM.

.TP 7
\ \ \'\fBm\fR\' :\fIToggle_Memory/Swap_Usage\fR \*(EM On/Off
This command affects two \*(SA lines.

.TP 7
\ \ \'\fBt\fR\' :\fIToggle_Task/Cpu_States\fR \*(EM On/Off
This command affects from 2 to many \*(SA lines, depending on the state
of the '1' toggle and whether or not \*(Me is running under true SMP.

.TP 7
\ \ \'\fB1\fR\' :\fIToggle_Single/Separate_Cpu_States\fR \*(EM On/Off
This command affects how the 't' command's Cpu States portion is shown.
Although this toggle exists primarily to serve massively-parallel SMP machines,
it is not restricted to solely SMP environments.

When you see 'Cpu(s):' in the \*(SA, the '1' toggle is \*O and all
\*(Pu information is gathered in a single line.
Otherwise, each \*(Pu is displayed separately as: 'Cpu0, Cpu1, ...'

.PP
\*(NT If the entire \*(SA has been toggled \*F for any window, you would be left
with just the\fB message line\fR.
In that way, you will have maximized available task rows but (temporarily)
sacrificed the program name in \*(FM or the \*(CW name when in \*(AM.

.\" ......................................................................
.SS 3c. TASK Area Commands
The \*(TA \*(CIs are\fB always\fR available in \*(FM.

The \*(TA \*(CIs are\fB never available\fR in \*(AM\fI if\fR the \*(CW's
\*(TD has been toggled \*F (\*(Xt 4. ALTERNATE\-DISPLAY Mode).

.PP
.\" .........................
.B APPEARANCE\fR of \*(TW
.br
.in +2
The following commands will also be influenced by the state of the
global 'B' (bold disable) toggle.
.in

.TP 7
\ \ \'\fBb\fR\' :\fIBold/Reverse_toggle\fR
This command will impact how the 'x' and 'y' toggles are displayed.
Further, it will only be available when at least one of those toggles is \*O.

.TP 7
\ \ \'\fBx\fR\' :\fIColumn_Highlight_toggle\fR
Changes highlighting for the current sort field.
You probably don't need a constant visual reminder of the sort field and
\*(Me hopes that you always run with 'column highlight' \*F, due to the cost
in path-length.

If you forget which field is being sorted this command can serve as a quick
visual reminder.

.TP 7
\ \ \'\fBy\fR\' :\fIRow_Highlight_toggle\fR
Changes highlighting for "running" tasks.
For additional insight into this task state, \*(Xt 2a. DESCRIPTIONS of Fields,
Process Status.

Use of this provision provides important insight into your system's health.
The only costs will be a few additional tty escape sequences.

.TP 7
\ \ \'\fBz\fR\' :\fIColor/Monochrome_toggle\fR
Switches the \*(CW between your last used color scheme and the older form
of black-on-white or white-on-black.
This command will alter\fB both\fR the \*(SA and \*(TA but does not affect the
state of the 'x', 'y' or 'b' toggles.

.PP
.\" .........................
.B CONTENT\fR of \*(TW
.PD 0
.TP 7
\ \ \'\fBc\fR\' :\fICommand_Line/Program_Name_toggle\fR
This command will be honored whether or not the 'Command' column
is currently visible.
Later, should that field come into view, the change you applied will be seen.

.TP 7
\ \ \'\fBf\fR\' and \'\fBo\fR\' :\fIFields_select\fR or \fIOrder_fields\fR
These keys display separate screens where you can change which
fields are displayed and their order.
For additional information on these \*(CIs
\*(Xt 2b. SELECTING and ORDERING Columns.

.TP 7
\ \ \'\fBH\fR\' :\fIThreads_toggle\fR
When this toggle is \*O, all individual threads will be displayed.  Otherwise, \*(Me displays a summation of all threads in a process.

.TP 7
\ \ \'\fBS\fR\' :\fICumulative_Time_Mode_toggle\fR
When 'Cumulative mode' is \*O, each process is listed with the \*(Pu
time that it and its dead children have used.

When \*F, programs that fork into many separate tasks will appear
less demanding.
For programs like 'init' or a shell this is appropriate but for others,
like compilers, perhaps not.
Experiment with two \*(TWs sharing the same sort field but with different 'S'
states and see which representation you prefer.

After issuing this command, you'll be informed of the new state of this toggle.
If you wish to know in advance whether or not 'Cumulative mode' is in
effect, simply ask for help and view the window summary on the second line.

.TP 7
\ \ \'\fBu\fR\' :\fIShow_Specific_User_Only\fR
You will be prompted to enter the name of the user to display.
Thereafter, in that \*(TW only matching User ID's will be shown, or possibly
no tasks will be shown.

Later, if you wish to monitor all tasks again, re-issue this command but
just press <Enter> at the prompt, without providing a name.

.PP
.\" .........................
.B SIZE\fR of \*(TW
.PD 0
.TP 7
\ \ \'\fBi\fR\' :\fIIdle_Processes_toggle\fR
Displays all tasks or just active tasks.
When this toggle is \*F, idled or zombied processes will not be displayed.

If this command is applied to the last \*(TD when in \*(AM, then it will not
affect the window's size, as all prior \*(TDs will have already been painted.

.TP 7
\ \ \'\fBn\fR\' or \'#\' :\fISet_Maximum_Tasks\fR
You will be prompted to enter the number of tasks to display.
The lessor of your number and available screen rows will be used.

When used in \*(AM, this is the command that gives you precise control over
the size of each currently visible \*(TD, except for the very last.
It will not affect the last window's size, as all prior \*(TDs will have
already been painted.

\*(NT If you wish to increase the size of the last visible \*(TD when in \*(AM,
simply decrease the size of the \*(TD(s) above it.

.PP
.\" .........................
.B SORTING\fR of \*(TW
.br
.in +2
For compatibility, this \*(Me supports most of the former \*(Me sort keys.
Since this is primarily a service to former \*(Me users, these commands do
not appear on any help screen.
   command   sorted field                  supported
     A         start time (non-display)      No
     M         %MEM                          Yes
     N         PID                           Yes
     P         %CPU                          Yes
     T         TIME+                         Yes

Before using any of the following sort provisions, \*(Me suggests that you
temporarily turn on column highlighting using the 'x' \*(CI.
That will help ensure that the actual sort environment matches your intent.

The following \*(CIs will\fB only\fR be honored when the
current sort field is\fB visible\fR.
The sort field might\fI not\fR be visible because:
     1) there is insufficient\fI Screen Width\fR
     2) the 'f' \*(CI turned it \*F
.in

.TP 7
\ \ \'\fB<\fR\' :\fIMove_Sort_Field_Left\fR
Moves the sort column to the left unless the current sort field is
the first field being displayed.

.TP 7
\ \ \'\fB>\fR\' :\fIMove_Sort_Field_Right\fR
Moves the sort column to the right unless the current sort field is
the last field being displayed.

.PP
.in +2
The following \*(CIs will\fB always\fR be honored whether or not
the current sort field is visible.
.in

.TP 7
\ \ \'\fBF\fR\' or \'\fBO\fR\' :\fISelect_Sort_Field\fR
These keys display a separate screen where you can change which field
is used as the sort column.

If a field is selected which was not previously being displayed, it will
be forced \*O when you return to the \*(Me display.
However, depending upon your screen width and the order of your fields,
this sort field may not be displayable.

This \*(CI can be a convenient way to simply verify the current sort field,
when running \*(Me with column highlighting turned \*F.

.TP 7
\ \ \'\fBR\fR\' :\fIReverse/Normal_Sort_Field_toggle\fR
Using this \*(CI you can alternate between high-to-low and low-to-high sorts.

.PP
.in +2
\*(NT Field sorting uses internal values, not those in column display.
Thus, the TTY and WCHAN fields will violate strict ASCII collating sequence.
.in

.\" ......................................................................
.SS 3d. COLOR Mapping
When you issue the 'Z' \*(CI, you will be presented with a separate screen.
That screen can be used to change the colors in just the \*(CW or
in all four windows before returning to the \*(Me display.

.P
.B Available \*(CIs
    \fB4\fR upper case letters to select a\fB target\fR
    \fB8\fR numbers to select a\fB color\fR
    normal toggles available\fR
        'B'       :bold disable/enable
        'b'       :running tasks "bold"/reverse
        'z'       :color/mono
    other commands available\fR
        'a'/'w'   :apply, then go to next/prior
        <Enter>   :apply and exit
        'q'       :abandon current changes and exit

If your use 'a' or 'w' to cycle the targeted window, you will
have applied the color scheme that was displayed when you left that window.
You can, of course, easily return to any window and reapply different
colors or turn colors \*F completely with the 'z' toggle.

The Color Mapping screen can also be used to change the \*(CW/field group
in either \*(FM or \*(AM.
Whatever was targeted when 'q' or <Enter> was pressed will be made current
as you return to the \*(Me display.


.\" ----------------------------------------------------------------------
.SH 4. ALTERNATE\-DISPLAY Mode
.\" ----------------------------------------------------------------------
.\" ......................................................................
.SS 4a. WINDOWS Overview
.TP
.B Field Groups/Windows\fR:
.br
In \*(FM there is a single window represented by the entire screen.
That single window can still be changed to display 1 of 4 different\fB field
groups\fR (\*(Xc 'G' \*(CI, repeated below).
Each of the 4 field groups has a unique separately configurable\fB \*(SA\fR
and its own configurable\fB \*(TA\fR.

In \*(AM, those 4 underlying field groups can now be made visible
simultaneously, or can be turned \*F individually at your command.

The \*(SA will always exist, even if it's only the message line.
At any given time only\fI one\fR \*(SA can be displayed.
However, depending on your commands, there could be from\fI zero\fR
to\fI four\fR separate \*(TDs currently showing on the screen.

.TP
.B Current Window\fR: