January 2001

Automating the Subst Command with VBScript

Operating systems: Windows 95/98/2000

by Gregory Shultz

If you store a lot of data on your hard drive, you probably use a very detailed folder structure in order to keep your data organized and to make it easy to find what you're looking for. For example, you might have a structure that has a main folder for your work, which contains other nested folders for each project category and months. Such a structure might look similar to the example shown in Figure A.

Figure A: Accessing your nested folders can mean that you spend a lot of time opening and closing folders.

While this type of folder structure keeps your data organized, it does require that you spend a lot of time opening and closing folders in Windows Explorer and your application's Open and Save As dialog boxes as you work. All this opening and closing of folders can be time consuming and frustrating.

Wouldn't it be nice if you could reference the path to a specific set of data folders with a single drive letter? If you're familiar with the old DOS commands, you know that you can do so quite easily with the Subst command.

For example, if you're working with the files in the Work\Project 1\1) January folder, you can use the Subst command to assign that path to drive letter W. Anytime you need to access files in that folder, you can just access drive W. Of course, that means that each time you want to assign a specific path to a drive letter, you have to open an MS-DOS Prompt window and manually type the commands to create the drive. This, too, can be time consuming and frustrating.

Fortunately, we discovered a way to automate the Subst command with the Windows Scripting Host and two scripts written in the VBScript language. These scripts will allow you to dynamically assign a drive letter for your nested data folders and delete that drive letter when you've finished. Once you begin using these handy scripts, you'll wonder how you ever lived without them.

In this article, we'll show you how to create two scripts in VBScript that will automate the procedure of using the Subst command to create a drive letter for your nested folders and delete it just as easily. As we do, we'll explain each step in detail.

Getting started

As we mentioned, our scripts will make use of the Subst command to create a drive letter for your nested folders as well as delete the drive letter. If you're not familiar with the Subst command, we recommend that you take a look at the sidebar "Understanding the Subst command." Doing so will help you understand and appreciate what the scripts are designed to automate. Furthermore, if typing in the commands to create the scripts isn't your cup of tea, don't worry--the scripts are available for download from our FTP site at ftp.elementkjournals.com/w9p/jan01.zip.

Creating the Make Work Drive script

Creating the Make Work Drive script is easy. To begin, launch Notepad and construct the Make Work Drive script shown in Figure B. Be sure that you type all the commands exactly as shown. If you don't, the script won't work correctly. When you've finished, save the file as Make Work Drive.vbs. Figure B: The Make Work Drive script automates using the DOS-based Subst command.

Studying the Make Work Drive script

Now that you've created the Make Work Drive script, let's take a step-by-step look at how the script works. Doing so now will give you a basic understanding of how the VBScript commands work in the script function and will make it easier for you to customize the script later.

The first line in the script defines the four variables, or placeholders, that the script uses to store information. We've used names that represent the information that the script stores in the variables. For example, the WinShell variable will hold special information about the Windows operating system, the prompt variable will hold the prompt that will appear in the dialog box, the folderpath variable will hold the path to the folders you want to work with, and the substcmd variable will hold the complete Subst command.

The second line activates the WinShell variable and provides it with access to some of the Windows operating system objects that the Windows Scripting Host makes available to the scripting languages. In this script, we'll take advantage of the objects that launch applications and display dialog boxes.

The third line assigns the text that will be the prompt in the dialog box to the prompt variable. The vbCrLf command at the end of each line of text is equivalent to pressing [Enter] after each line of text. This makes it possible to format the contents of the dialog box.

The next command line uses the InputBox command to create the dialog box, which waits for input from the user. When the user types a path in the text box and clicks OK or leaves the text box blank and clicks Cancel, the result is assigned to the folderpath variable.

The next eight lines make up the If...Then...Else statement, which analyzes the value in the folderpath variable and performs one of two actions. The first part of the statement checks to see if the folderpath variable is empty. If it is, then the user either clicked Cancel or clicked OK without filling in the text box. Either way, if the folderpath variable is empty, the Wscrpt.Quit command terminates the script.

If the folderpath variable contains text, the script jumps to the commands that follow the Else statement. There, the substcmd variable is assigned a text string that includes the command subst w: as well as the path that's stored as a text string in the folderpath variable.

The next line then uses the WinShell.Run command to run the DOS-based Subst command, which assigns the path to the drive letter W. As soon as the Subst command creates the drive, the script opens a My Computer-style window and displays the contents of drive W.

The next two lines contain optional commands that allow the script to display the contents of drive W in a Windows Explorer-style window. These lines are disabled by virtue of the apostrophe (`) at the beginning of each line. If you're satisfied with a My Computer-style window, you can leave these commands disabled.

However, if you'd prefer to see the contents of drive W in a Windows Explorer-style window, all you have to do is delete the apostrophe marks, as shown in Figure C. When you do, the MsgBox command will immediately display a prompt and prevent the script from opening a My Computer-style window. When you click OK, the following WinShell.Run command displays the contents of drive W in a Windows Explorer-style window.

Figure C: If you'd prefer to use a Windows Explorer-style window, simply delete the apostrophe marks in front of the two disabled lines.

Regardless of which window style you decide to go with, the End If command closes the If...Then...Else statement. Then the Wscrpt.Quit command terminates the script.

Creating the Delete Work Drive script

Once you've run the Make Work Drive script, you'll need a way to delete the work drive should you want to assign the drive letter to another path. To do so, you'll use the Delete Work Drive script.

To create the Delete Work Drive script, launch Notepad and construct the script shown in Figure D. Be sure that you type all the commands exactly as shown. If you don't, the script won't work correctly. When you've finished, save the file as Delete Work Drive.vbs.

Figure D: This script will delete the work drive.

Studying the Delete Work Drive script

Now that you've created the Delete Work Drive script, let's take a step-by-step look at how the script works. To begin with, the script defines the three variables that it uses to store information. Again, we've used names that represent the information that the script stores in the variables. Just like in the Make Work Drive script, the WinShell variable will hold special information about the Windows operating system. The FileShell variable will hold special information about file management and workdrv will hold the drive letter assigned to the work drive.

The second line activates the WinShell variable and provides it with access to some of the Windows operating system objects just like it did in the Make Work Drive script. It will allow access to the objects that launch applications and display dialog boxes.

The third line activates the FileShell variable and provides it with access to some of the file management objects the Windows Scripting Host makes available to the scripting languages. In the Delete Work Drive script, we'll take advantage of the object that allows us to examine drive letters.

The fourth line simply assigns the workdrv variable the letter assigned to the work drive. In this case, the work drive is assigned to the letter w.

The next six lines make up an If...Then...Else statement, which determines if the drive letter W is present and performs one of two actions. If drive W is present, the first part of the statement uses the WinShell.Run command and launches the subst /d command to delete the drive letter. Then, the MsgBox command displays a message letting the user know that the drive has been deleted.

If drive W isn't present, it either hasn't been created yet or it's already been deleted. In either case, the following MsgBox command displays a message letting the user know that the drive isn't present.

The End If command then closes the If...Then...Else statement. Finally, the Wscrpt.Quit command terminates the script.

Using the scripts

Using the scripts is easy. To make using the scripts as convenient as possible, you can create shortcuts to the scripts and then put the shortcuts on the desktop, the Start menu, the Quick Launch toolbar, or on a custom toolbar--wherever you think they would be most convenient for you.

Now, when you double-click on the Work Drive script shortcut, you'll see the Where Do You Want To Work Today? dialog box. You'll then type the path to the folder that you want to work with in the text box, as shown in Figure E, and click OK. Keep in mind that you must enclose the path in double quotes if it includes spaces.

Figure E: You'll type the path to the folder that you want to work with in the text box.

If you decide that you don't want to create drive W at this point, you can just click Cancel. When you do, the Where Do You Want To Work Today? dialog box disappears.

If after you create your work drive you want to delete it, just double-click on the Delete Work Drive shortcut. When you do, you'll see the message box shown in Figure F. If you forget that you previously deleted the work drive and double-click on the Delete Work Drive shortcut, you'll see the message box shown in Figure G.

Figure F: When you double-click on the Delete Work Drive shortcut, the script informs you that the operation was successful.

Figure G: If the work drive isn't present when you double-click on the Delete Work Drive shortcut, you'll see this message box.

Conclusion

If you use a detailed folder structure to keep your data organized, you probably spend a lot of time opening and closing folders as you work. In this article, we've shown you how to simplify this task by using VBScript to automate the use of the Subst command.

Copyright © 2001 Element K Content LLC. All rights reserved. Reproduction in whole or in part in any form or medium without express written permission of Element K Content LLC is prohibited. Element K is a service mark of Element K LLC.