How to use a PowerShell function return as a variable in a batch file

I was trying to use the return from myPowershellScript.ps1 to use as a variable in my batch file.

myPowershellScript.ps1

function GetLatestText
{
    return "Hello World"
}

I was trying to use the For /F function. There may be a better way.

myBatch.bat

for /f "delims=" %%a in (' powershell -command "\\Rossi2\Shared\myPowershellScript.ps1" ') do set "var=%%a"

echo %var%

Desired output, would be to have ‘Hello World’ output in the cmd window.

I was trying to use the batch file as some old processes use them. For newer processes I do everything in PowerShell and it works fine.

The current output is blank.

>Solution :

• Your syntax for trying to capture output from a PowerShell script from a batch file is correct (assuming single-line output from the script),^[1] except that it it is more robust to use the -File parameter of powershell.exe, the Windows PowerShell CLI than the -Command parameter.

  • See this answer for when to use -File vs. -Command.

• Your problem is with the PowerShell script itself:

  • You’re defining function Get-LatestText, but you’re not calling it, so your script produces no output.

  • There are three possible solutions:

    • Place an explicit call to Get-LatestText after the function definition; if you want to pass any arguments received by the script through, use Get-LatestText @args

    • Don’t define a function at all, and make the function body the script body.

    • If your script contains multiple functions, and you want to call one of them, selectively: in your PowerShell CLI call, dot-source the script file (. <script>), and invoke the function afterwards (this does require -Command):

       for /f "delims=" %%a in (' powershell -Command ". \"\\Rossi2\Shared\myPowershellScript.ps1\"; Get-LatestText" ') do set "var=%%a"
      
       echo %var%
      

^{[1] for /f loops over a command’s output line by line (ignoring empty lines), so with multiline output only the last line would be stored in %var% – more effort is needed to handle multiline output.}