Scripts are simple text files that you
create using Notepad or some other text editor. You can use a word
processor such as WordPad to create scripts, but you must make sure
that you save these files using the program’s Text Only document type.
For VBScript, a good alternative to Notepad is the editor that comes
with either Visual Basic or any program that supports VBA (such as the
Office suite). Just remember that VBScript is a subset of VBA (which
is, in turn, a subset of Visual Basic), so it does not support all
objects and features.
In a web page, you use the <script> tag to specify the scripting language you’re using, as in this example:
<SCRIPT LANGUAGE="VBScript">
With the WSH, the script file’s extension specifies the scripting language:
For VBScript, save your text files using the .vbs extension (which is registered as the following file type: VBScript Script File).
For JavaScript, use the .js extension (which is registered as the following file type: JScript Script File).
As described in the next three sections, you have
three ways to run your scripts: by launching the script files directly,
by using WSscript.exe, or by using CScript.exe.
Running Script Files Directly
The easiest way to run a script from within Windows is to launch the .vbs or .js
file directly. That is, you either double-click the file in Windows
Explorer or type the file’s path and name in the Run dialog box. Note,
however, that this technique does not work at the command prompt. For
that, you need to use the CScript program described a bit later.
Using WScript for Windows-Based Scripts
The .vbs and .js file types have an open method that’s associated with WScript (WScript.exe), which is the Windows-based front-end for the WSH. In other words, launching a script file named MyScript.vbs is equivalent to entering the following command in the Run dialog box:
The WScript host also defines several parameters
that you can use to control the way the script executes. Here’s the
full syntax:
WSCRIPT [filename] [arguments] [//B] [//D] [//E:engine] [//H:host] [//I] [//Job:xxxx] [//S] [//T:ss] [//X]
| filename | Specifies the filename, including the path of the script file, if necessary. |
| arguments | Specifies optional arguments required by the script. An argument is a data value that the script uses as part of its procedures or calculations. |
| //B | Runs the script in batch mode, which means script errors and Echo method output lines are suppressed. |
| //D | Enables
Active Debugging. If an error occurs, the script is loaded into the
Microsoft Script Debugger (if it’s installed), and the offending
statement is highlighted. |
| //E:engine | Executes the script using the specified scripting engine, which is the scripting language to use when running the script. |
| //H:host | Specifies the default scripting host. For host, use either CScript or WScript. |
| //I | Runs the script in interactive mode, which displays script errors and Echo method output lines. |
| //Job:id | In a script file that contains multiple jobs, executes only the job with idid. attribute equal to |
| //S | Saves the specified WScript arguments as the default for the current user; uses the following Registry key to save the settings:
HKCU\Software\Microsoft\Windows Script Host\Settings
|
| //TT:ss | Specifies the maximum time in seconds (ss) that the script can run before it shuts down automatically. |
| //X | Executes the entire script in the Microsoft Script Debugger (if it’s installed). |
For example, the following command runs MyScript.vbs in batch mode with a 60-second maximum execution time:
wscript myscript.vbs //B //TT:60
|
A script job is a
section of code that performs a specific task or set of tasks. Most
script files contain a single job. However, it’s possible to create a
script file with multiple jobs. To do this, first surround the code for
each job with the <script> and </script> tags, and then surround those with the <job> and </job> tags. In the <job> tag, include the id attribute and set it to a unique value that identifies the job. Finally, surround all the jobs with the <package> and </package> tags. Here’s an example:
<package>
<job id="A">
<script language="VBScript">
WScript.Echo "This is Job A."
</script>
</job>
<job id="B">
<script language="VBScript">
WScript.Echo "This is Job B."
</script>
</job>
</package>
Save the file using the .wsf (Windows Script File) extension.
|
Note
If
you write a lot of scripts, the Microsoft Script Debugger is an
excellent programming tool. If there’s a problem with a script, the
debugger can help you pinpoint its location. For example, the debugger
enables you to step through the script’s execution one statement at a
time.
Using CScript for Command-Line Scripts
The WSH has a second host front-end application called CScript (CScript.exe),
which enables you to run scripts from the command line. In its simplest
form, you launch CScript and use the name of the script file (and its
path, if required) as a parameter, as in this example:
The WSH displays the following banner and then executes the script:
Microsoft (R) Windows Script Host Version 5.8 for Windows
Copyright (C) Microsoft Corporation. All rights reserved.
As with WScript, the CScript host has an extensive set of parameters you can specify:
CSCRIPT [filename] [arguments] [//B] [//D] [//E:engine] [//H:host] [//I]
[//Job:xxxx] [//S] [//T:ss] [//X] [//LOGO | //NOLOGO] [//U]
This syntax is almost identical to that of WScript, but it adds the following three parameters:
| //LOGO | Displays the WSH banner at startup |
| //NOLOGO | Hides the WSH banner at startup |
| //U | Uses Unicode for redirected input/output from the console |
Script Properties and .wsh Files
In the previous two sections, you saw that the
WScript and CScript hosts have a number of parameters you can specify
when you execute a script. It’s also possible to set some of these
options by using the properties associated with each script file. To
see these properties, right-click a script file and then click
Properties. In the properties sheet that appears, display the Script
tab, shown in Figure 1. You have two options, as follows:
Stop Script After Specified Number of Seconds—
If you activate this check box, Windows shuts down the script after it
has run for the number of seconds specified in the associated spin box.
This is useful for scripts that might hang during execution. For
example, a script that attempts to enumerate all the mapped network
drives at startup might hang if the network is unavailable.
Display Logo When Script Executed in Command Console—
As you saw in the previous section, the CScript host displays some
banner text when you run a script at the command prompt. If you
deactivate this check box, the WSH suppresses this banner (unless you
use the //LOGO parameter).
When you make changes to these properties, the WSH
saves your settings in a new file that has the same name as the script
file, except with the .wsh (WSH Settings) extension. For example, if the script file is MyScript.vbs, the settings are stored in MyScript.wsh. These .wsh files are text files organized in sections, much like .ini files. Here’s an example:
[ScriptFile]
Path=C:\Users\Administrator\My Documents\Scripts\DisplayHomeServerUptime.vbs
[Options]
Timeout=10
DisplayLogo=0
To use these settings when running the script, use either WScript or CScript and specify the name of the .wsh file:
Note
Rather than setting properties for individual
scripts, you might prefer to set global properties that apply to the
WScript host. Those global settings then apply to every script that
runs using the WScript host. To do this, run WScript.exe without parameters. This displays the properties sheet for WScript, which contains only the Script tab shown in Figure 1. The settings you choose in the properties sheet are stored in the following Registry key:
HKLM\Software\Microsoft\Windows Script Host\Settings
