[vbscript] How do I rename a file using VBScript?

Rename filename by searching the last character of name. For example, 

Original Filename: TestFile.txt_001
Begin Character need to be removed: _
Result: TestFile.txt

Option Explicit

Dim oWSH
Dim vbsInterpreter
Dim arg1 'As String
Dim arg2 'As String
Dim newFilename 'As string

Set oWSH = CreateObject("WScript.Shell")
vbsInterpreter = "cscript.exe"

ForceConsole()

arg1 = WScript.Arguments(0)
arg2 = WScript.Arguments(1)

WScript.StdOut.WriteLine "This is a test script."
Dim result 
result = InstrRev(arg1, arg2, -1)
If result > 0 then
    newFilename = Mid(arg1, 1, result - 1)
    Dim Fso
    Set Fso = WScript.CreateObject("Scripting.FileSystemObject")
    Fso.MoveFile arg1, newFilename
    WScript.StdOut.WriteLine newFilename
End If



Function ForceConsole()
    If InStr(LCase(WScript.FullName), vbsInterpreter) = 0 Then
        oWSH.Run vbsInterpreter & " //NoLogo " & Chr(34) &     WScript.ScriptFullName & Chr(34)
        WScript.Quit
    End If
 End Function