Scripting Windows 7 with WSH : Scripts and Script Execution

Scripts and Script Execution

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 Windows Script Host, 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 Windows Script Host. In other words, launching a script file named MyScript.vbs is equivalent to entering the following command in the Run dialog box:

wscript myscript.vbs

The WScript host also defines several parameters that you can use to control how the script executes. Here’s the full syntax:

WSCRIPT filename arguments //B //D //E:engine //H:host //I //Job:xxxx //S //T:ss //X

					  

HKCU\Software\Microsoft\Windows Script Host\Settings

For example, the following command runs MyScript.vbs in batch mode with a 60-second maximum execution time:

wscript myscript.vbs //B //TT:60

<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>

Using CScript for Command-Line Scripts

The Windows Script Host 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:

cscript myscript.vbs

The Windows Script Host 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 //U //LOGO //NOLOGO

					  

This syntax is almost identical to that of WScript, but adds the following three parameters:

Script Properties and .wsh Files

In the preceding 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:

• 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 Windows Script Host suppresses this banner (unless you use the //LOGO parameter).

When you make changes to these properties, the Windows Script Host saves your settings in a new file that has the same name as the script file, except with the .wsh (Windows Script Host 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 into sections, much like .ini files. Here’s an example:

[ScriptFile]
Path=C:\Users\Paul\Documents\Scripts\Popup1.vbs
[Options]
Timeout=0
DisplayLogo=1

To use these settings when running the script, use either WScript or CScript and specify the name of the .wsh file:

wscript myscript.wsh

HKLM\Software\Microsoft\Windows Script Host\Settings

Running a Script as the Administrator

When you run scripts in Windows 7, you may on occasion need to run those scripts under the auspices of the Administrator account.

When you need to run a script under the Administrator account, one solution is to first launch an elevated Command Prompt session. From the elevated command line, you could then use CScript to launch the script, as described earlier. That would work, but it’s a bit of a hassle. If you run a lot of administrator scripts, you’d probably prefer something a lot more direct.

I’m happy to report that a much more direct method is available. You can tweak the Windows 7 file system to display a Run as Administrator command when you right-click a VBScript file. Click that command, enter your UAC credentials, and your script runs with administrator privileges.

Here’s what you do:

HKEY_CLASSES_ROOT\VBSFile\Shell

"C:\Windows\System32\WScript.exe" "%1" %*

"C:\Windows\System32\WScript.exe" "%1" %*

Figure 2 shows the modified Registry. With these tweaks in place, right-click a VBScript file and you see the Run as Administrator command, as shown in Figure 3.

Figure 2. The dialog box that’s displayed when you run the script.

Figure 3. Tweaking the Windows 7 Registry to add the Run as Administrator command to the shortcut menu of any VBScript file.