Windows.XP.in.a.Nutshell.1002005.2Ed [Electronic resources] نسخه متنی

6.1. Using the Command Line

The premise of the
command prompt is simple enough: commands are typed, one at a time,
at a blinking cursor. The commands are then issued when the Enter key
is pressed. After the command has completed, a new prompt is shown,
allowing additional commands to be typed.

Some commands are fairly rudimentary, requiring only that you type
their name. Other commands are more involved and can require several
options (sometimes called arguments or command-line parameters). For
example, the del command (discussed later in this
chapter) is used to delete one or more files; it requires that the
name of the file be specified after the command, like this:

del /p myfile.txt

Here, myfile.txt is the filename to be deleted
and /p is an extra option used to modify the
behavior of del. The fact that this usage is not
limited to internal commands (like del) is what
makes the command line (but not necessarily the Command Prompt
application) such an important part of Windows XP's
design. For example:

notepad myfile.txt

is what Windows executes behind the scenes, by default, when you
double-click the myfile.txt icon in Explorer.
Notepad (discussed in Chapter 4) is effectively
a "command" here. If you type the
filename of any existing file at the command prompt, it instructs
Windows to launch that file. This works for applications, Windows
Shortcuts, batch files, documents, or any other type of file; the
only requirement is that the file be located in the current working
directory (see "cd or chdir", later
in this chapter) or in a folder specified in the path (also discussed
later in this chapter).

Specifying a filename as an argument when launching Notepad (such as
myfile.txt in the example above) from the
command prompt instructs Notepad to open that file. Throughout this
book, you'll see references to a
component's command-line syntax that documents these
otherwise hidden features. Since every program and command has its
own set of command-line options, it's best to get a
feel for the way they work in general rather than trying to commit
them all to memory.

If you've executed a command that takes a long time
to complete, such as one that displays a great deal of information on
the screen, you can interrupt it by pressing Ctrl-C.

Open the control menu of any open Command Prompt window (click the
little icon in the top left of the window or press Alt-Space) and
select Properties to customize the look and feel of the command
prompt window. An important option here is Layout
Screen Buffer Size
Height, which controls
the number of lines kept in memory; this enables you to scroll up to
view a history of your entire session. This is useful, for example,
if you're looking at long directory listings. Note
that this is not the same as Options
Buffer Size, which
contains a "most frequently used"
list of typed commands; use the up-and-down arrow keys at the prompt
to cycle through them.

Copy and paste operations are also
possible at the Command Prompt, but not using the traditional
keyboard shortcuts: Ctrl-X, Ctrl-C, and Ctrl-V won't
work here. If QuickEdit is enabled (Properties
Options
QuickEdit mode), text can
be highlighted at any time with the mouse, copied to the clipboard by
pressing Enter, and pasted by clicking anywhere in the window with
the right mouse button. If QuickEdit is disabled (the default),
right-clicking will display the Edit menu; select Mark to begin
highlighting text and then go to Edit
Copy or simply press
Enter to copy the text to the clipboard.

Finally, the prompt itself, known as the

caret (>), is usually
accompanied by a folder name representing the current working
directory. Note that the term
"directory" is synonymous with
"folder," and is used throughout
this chapter only because it is customary when discussing the command
prompt.

See "Command Prompt" in Chapter 4 for more information on the
cmd.exe application and its command-line
parameters. Of special interest is the /e
parameter, which enables or disables "command
extensions," additional features documented
throughout this chapter.