Chapter 9. The Windows Script Host

One of the features that has distinguished operating systems like Unix and Linux from Windows is that they've made it relatively easy to write scripts that automate repetitive tasks . Since doing the same thing over and over again is one of the basic labor-saving benefits of a computer, the lack of robust scripting capabilities has always been one of the great weaknesses of Windows.

Originally released as part of Windows 98, the Windows Script Host (WSH) is Microsoft's answer to this problem and a replacement for the remarkably limited batch file language (see Chapter 6). The addition of WSH to the Windows platform represents a major step forward in Windows' role in the networking world.

WSH provides a way to automate Windows-based graphical applications using any one of several, powerful, full-featured scripting languages. WSH provides a set of objects that allow you to interact with the network, Registry, files and folders, and even other applications, using scripting languages such as VBScript and Microsoft JScript (a JavaScript-like language). Third-party add-ons that provide the same functionality in other scripting languages, such as Perl, Tcl, REXX, and Python, are also available.

WSH scripts can be used to create network login scripts that are more complex than those that are built into Windows, and can be used to automate local Desktop tasks. The resulting scripts can be run from the Desktop, from the command line, or via the Explorer's Scheduled Tasks. WSH scripts can also be embedded in HTML files, which in turn can be used as part of the Active Desktop.

Unfortunately, while WSH is powerful, it is not for the faint-hearted. If you do not already know a scripting language such as VBScript, JavaScript, or Perl, you should get a good book on the language of your choice before starting out. Learning VBScript , by Paul Lomax; JavaScript, The Definitive Guide , by David Flanagan; and Learning Perl on Win32 Systems , by Randal Schwartz, Erik Olson, and Tom Christiansen, are three useful books available from O'Reilly.

This chapter shows how to run WSH scripts, gives a brief introduction to VBscript programming, and describes the syntax of the objects provided by WSH. It also describes how to use the Object Browser to discover information about system and application objects, and concludes with some practical examples that illustrate the power of WSH scripts.

Scripts created on Windows XP can be run on other versions of Windows, as long as they have the Windows Script Host component installed (it's an option on some earlier versions.) Note also that the version of WSH that comes with Windows XP may be more recent than the ones included with previous versions of Windows, so you may need to obtain updates from http://www.microsoft.com and install them on any target machines.