Automating VBS -> Powershell Conversion

[albvar]

I have several hundred VBS files that need conversion, but I've found using Invoke-OAIChat (gpt-o model) with instructions and a conversation prompt to be somewhat unreliable. The results tend to be hit or miss when it comes to following the instructions accurately. Is there a more effective approach I should consider?

I am sharing my prompt below:

Task: Convert the provided VBScript into a PowerShell script that meets the following requirements. Review finished script thouroughly to ensure there aren't any errors and that all guidelines have been thouroughly followed before providing a response.

Environment: Make this strictly compatible with Windows powershell 5.1.

Assumptions:
1: The VBScript is for deployment as a Win32 application within Microsoft Intune.
2: Omit application detection logic (handled by Intune).
3: Focus solely on translating and refining the core functionality.
4: When the file name contains install in the name omit any application detection logic from being converted into powerhsell.
5: Carefully follow the guidelines numbered below without skipping and in the order shown.

Guidelines:
1: Use approved verb-noun (Get-, New-) when creating new function names. Use pascal casing for function parameter variables.
2: Use descriptive variable names, proper indentation, and error handling.
3: Leverage `$PSScriptRoot` for the script location.
4: Use string formatting using the -f operator where applicable
5: Limit lines to 160 characters; prefer vertical stacking for arrays.
6: Implement `Write-Log` to output to console and log file. Capturing log levels (Info, Warning, Error) with timestamps.
9: Start the script with a PowerShell help block.
10: Include a summary, parameter descriptions, and relevant comments from the original VBScript.
11: Avoid using ; to delineate different commands, instead use a new line.
12. Avoid using the call operator &, leverage Start-Process instead
13: Use `Join-Path` for directory and file paths.
14: Prefer arrays over string concatenation for command arguments (e.g., `msiexec.exe`). Ensure that Arguments is an array properly formatted.
15: Use single quotes for static strings and double quotes " for embedding variables.
16: Avoid user-specific environment variables (e.g., `%USERPROFILE%`), using system-wide paths (e.g., `C:\Windows\System32\config\systemprofile`).
17: Treat uninstallation as non-critical (log failure as a warning), while installation is critical (halt on failure).
18: Wrap non-critical operations in try/catch blocks.
19: Define and process arrays of commands (with `Command`, `Arguments`, and `IsCritical` fields) and handle failures appropriately.
20: Ensure the script logs both successes and failures.
21: Do not use reserved variables like `$Args`. Define explicit parameters in the function or script header, and ensure parameters are passed correctly. Avoid using any implicit parameter arrays.

Outcome: Provide only the complete PowerShell script, no additional explanations.

[dfinke]

Thanks for sharing the prompt @albvar. Really great application of AI too!

That is a lot of directions for the model to follow. Too bad the new OpenAI o1-preview reasoning models are not yet available to the API, it'd be very interesting to see how it handles it, it wouldn't be 100%.

Also, how large are the VBS files? That too will be challenging for the model.

Off the top of my head, breaking this down into multiple steps would be how I'd approach it.

Something like, pass in the VBS, with the assumptions and the first three guidelines. Save the results. Then take those results, pass it in, with the assumptions and the next three guidelines. So maybe there would be seven passes.

This is defintely where this is "art." Figuring out how the model best works with a complicated VBS + the assumptions + guidelines.

The model is an intern that has read everything on the planet. Following directions over a complicated scripts made need more hand holding.

Would love to see an example of a VBS. Happpy to discuss approaches.

Super use case!

[albvar]

Thank you for your response. On average, the VBScript files are 5KB or smaller, which equates to about 100 lines of code. I have roughly 400 scripts to convert. I appreciate your insight and will attempt to split the guidelines in half until I achieve the desired results.

Would you recommend using Invoke-OAIChat, or would creating a new chat assistant with the code_interpreter tool be a better fit for this use case?

Set oShell = CreateObject("WScript.Shell")
Set shortcut = oShell.CreateShortcut("C:\Users\Public\Desktop\YourAppShortcut.lnk")
Set objFSO = CreateObject ("Scripting.FileSystemObject")
set oEnv = oShell.Environment("PROCESS")
strProgramFiles = oShell.ExpandEnvironmentStrings("%Windir%")
strProgram = oShell.ExpandEnvironmentStrings("%Programdata%")
strProgramFiles = oShell.ExpandEnvironmentStrings("%ProgramFiles(x86)%")
strtemp = oShell.ExpandEnvironmentStrings("%temp%")

' Set the IE Security Environment Variable (http://support.microsoft.com/?id=889815)
oEnv("SEE_MASK_NOZONECHECKS") = 1
scriptFullName = wscript.scriptFullname
ScriptFolderName = left(scriptFullName, InStrRev(ScriptFullName, "\"))

strvalue = oShell.ExpandEnvironmentStrings("%store%")
sText = Right(strvalue, 4)

strCmd1 = chr(34) & strSysDir & "\YourApp\PROD\uninst.exe" & Chr(34) & " /S"
strcmd2 = "msiexec.exe /x {GUID-1} /qn /l*v "  & chr(34) & "%windir%\Logs\YourApp_9.1.0.1_uninstall.log" & chr(34)
strcmd5 = "msiexec.exe /x {GUID-2} /qn /l*v "  & chr(34) & "%windir%\Logs\YourApp_9.2.0.3_uninstall.log" & chr(34)

strCmd3 = chr(34) & ScriptFolderName & "YourAppInstaller.exe" & chr(34) & " /q /installType=0 /facilityID=" & sText & " /targetEnv=PROD /encryptFacility=0 /S /installUser=yourUser /installPasswd=yourPassword /D=C:\YourApp\PROD"
strcmd4 = "msiexec.exe /i " & chr(34) & ScriptFolderName & "YourApp_9.2.0.9.msi" & chr(34) & " /qn /l*v " & chr(34) & "%windir%\Logs\YourApp_9.2.0.9_install.log" & chr(34)

Wscript.Echo strcmd4

If objFSO.FileExists (strSysDir & "\YourApp\PROD\uninst.exe") Then
	ret1 = oShell.Run(strCmd1,0, True)
End If

If IsInstalled("{GUID-1}") Then
	ret2 = oShell.Run(strcmd2,0, True)
End If 

If IsInstalled("{GUID-2}") Then
	ret2 = oShell.Run(strcmd5,0, True)
End If 

ret3 = oShell.Run(strCmd3,0, True)

If ret3 = 0 Or ret3 = 3010 Then
	ret4 = oShell.Run(strcmd4,0, True)
	If ret4 = 0 Or ret4 = 3010 Then
		WScript.Sleep 3000		
		shortcut.TargetPath = "C:\YourApp\PROD\YourAppLauncher.bat"
		shortcut.Arguments = sText
		shortcut.IconLocation = "C:\YourApp\PROD\app_icon.ico"   
		shortcut.workingdirectory= "C:\YourApp\PROD"
		shortcut.Save
		WScript.quit ret4
	Else 
		WScript.quit ret4
	End If 
Else 
	WScript.Quit ret3
End If

sub InstallExecute(strCommandLine)
	on error resume next
	ret = oShell.Run(strCommandLine,0, True)
	if err.number <> 0 then
		'WScript.quit err.number
	end if
	on error goto 0
  
	if ret <> 0 AND ret <> 3010 then
		'WScript.quit ret
	end if
end Sub

Public Function IsInstalled(strGUID)
	On Error Resume Next
	Dim objInstaller
	Dim strProduct, strInstalledProducts
	
	Set objInstaller = WScript.CreateObject("WindowsInstaller.Installer")
	Set strInstalledProducts = objInstaller.Products
	
	IsInstalled = False
	For Each strProduct In strInstalledProducts
		If UCase(strProduct) = UCase(strGUID) Then
			IsInstalled = True
		End If
	Next
End Function

[dfinke]

Thanks for that. Good question on the chat or code_interpreter. The code_interpreter spins up a Python enviroment and I would experiment with that. Try that in the playground, paste your VBS and some guidelines.

Then you can model the assistant with PSAI to further automate. Invoke-OAIChat essentially wraps that so it is easy to work with assistants, threads, runs, waiting, and messages.

Good Stuff

Looks like the VBS is involved. Never tried what you are doing. Early on AI models were not doing PowerShell very well. Also, I don't think there are a lot of places that hold VBS code, like GitHub, so the model training may not be the best. Then again, it looks like VB code, so.

AI models have been trained on COBOL, and folks are using it to migrate to Java.

You're in real experimental space.

I'm also wondering if you could fine-tune a model with a couple hundred examples of VBS -> PS might really help.

80/20 see how far prompting can take you.

I would also consider trying all the code+prompt in Claude - cheap to get credits. Sonnet is a but better thatn 4o.

Also - we are only a few weeks away from seeing of OpenAI drops GPT-5.

Prompt engineering muscle is worth building at this point is.