Manipulate Text File Using VBA

I had a problem today where I had to make some changes to a couple of large text files (100mb+). It seems that the File System Object (Microsoft Scripting Runtime) can only read or write at any one time so I ended up writing this. It opens two text streams at once , one to read and one to write and creates a revised file. Not very exciting but I thought somebody might find it useful ...

Sub ChangeTextFile()
' Manipulating a text file with VBA
' Loops through text file and creates revised one
' This code requires a reference (Tools > References) to Microsoft Scripting Runtime
Dim FSO As FileSystemObject
Dim FSOFile As TextStream, FSOFileRevised As TextStream
Dim FilePath As String, FilePathRevised As String
FilePath = "c: est.txt" ' create a test.txt file or change this
' adds "_Revised" to your file name
FilePathRevised = Left(FilePath, Len(FilePath) - 4) & "_Revised" & Right(FilePath, 4)........................