Reading and Writing Files with the VBScript FileSystemObject

By Stephen Bucaro

Scripts are (usually) small interpreted (meaning they don't get compiled) programs that you can write using a simple text editor like Windows Notepad. VBScript stands for "Visual Basic Script", which means it's written in Microsoft's easy to understand Visual Basic language. The scripts are interpreted and executed by a program called the "Windows Scripting Host", (WSH) which is installed on Windows computers by default.

It's easy to run a VBScript in the WSH, all you have to do is give the text file containing the code a the .vbs file extension, then double-click on the file name. When you run a VBScript it has access to the VBScript runtime objects. Reading and writing files uses two of these objects: the FileSystemObject gives your script access to the computer's file system, the TextStream object lets your script open, read, and write to text files.

To access the computer's file system, you must create a FileSystemObject with the CreateObject method:

Dim objFSO
Set objFSO = CreateObject("Scripting.FileSystemObject")

The FileSystemObject's CreateTextFile method creates a text file and returns a TextStream object that can be used to read or write to the file:

Dim objFSO, objTextFile
Set objTextFile = objFSO.CreateTextFile(filename, overwrite, unicode)

The filename argument specifies the path and name of the file. The overwrite argument is a Boolean value that specifies whether you can overwrite an existing file (true = overwrite, false = do not overwrite).

The unicode argument specifies whether the file will be Unicode (a 32 bit standard for encoding multiple international languages) or ASCII (a 7 bit code for encoding English) (true = Unicode false = ASCII).

The FileSystemObject's OpenTextFile method opens an existing text file and returns a TextStream object that can be used to read or write to the file:

Dim objFSO, objTextFile
Set objTextFile = objFSO.OpenTextFile(filename, mode, create, unicode)

The filename argument specifies the path and name of the file. The mode argument requires a constant value (1 to open the file for reading; 2 to open the file writing; 8 to open the file for appending).

The create argument is a Boolean value that specifies whether a new file should be created if the specified file does not exist (true = create false = do not create).

The unicode argumment specifies whether the file will be opened in Unicode format or ASCII format (true = Unicode false = ASCII).

TextStream Object Methods

Once the file is opened you use one of the following methods to read from or write to the file:

ReadAll reads the entire text file and returns a text string.

Dim fileText
fileText =  objTextFile.ReadAll

ReadLine reads one line of text from a file. It reads up to, but does not include the new-line character.

Dim fileText
fileText =  objTextFile.ReadLine

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