Question

I wrote several Powershell scripts which deploy software for a client. I used Write-Host to output a lot of information so that the progress of the deploy can be watched and they call this from one of their deploy application using Start-Transcript to capture this output.

However, they also need to be able to call some of these scripts from another application which can only capture output from stdout. This means that Write-Host won’t work there since it outputs only to the console or host and doesn’t get directed to stdout (correct?)

My thought was that I could change the code to use Write-Out instead, except that this causes another problem. Since I use functions and since functions in Powershell “return” everything that goes to stdout to the caller that would likely screw up any of my code that retrieves output from a function.

Is there a way to direct output to stdout from a function without it going to the calling code as the output of the function itself? Here is an example of the problem:

function Test-Output ([int]$number) {
    Write-Output "This is a string"
    return $number
}

[int]$someNumber = Test-Output 10

$someNumber

If you run the code above you’ll see an error because Powershell is trying to assign “This is a string” to the integer $someNumber. If you change the variable to a string then it will capture the full output of the function (This is a string 10) and assign it to the variable.

Thanks for any suggestions that you can give!

Answer 1

Try this.

function Add-Numbers {
    param (
        [double] $FirstNumber,
        [double] $SecondNumber
    )

    Write-Host "Hello World"

    return ($FirstNumber + $SecondNumber)
}

$result = Add-Numbers 1 2

#Write-Host "Result is $result"