PowerShell - script 1 calls script 2 - how to return value from script 2 to script 1

Question

I have two PowerShell scripts. One script invokes another PowerShell script using elevated credentials, using Start-Process.

But I am struggling with how to make the second script return the output value to the first script.

Here is script # 1, which is invoked with script1.psl "sender-ip=10.10.10.10"

function getUser($abc) {

    <#Previously created password file in C:\Script\cred.txt, read-host -assecurestring | convertfrom-securestring | out-file C:\Script\cred.txt#>

    $password = get-content C:\Script\cred.txt| convertto-securestring
    $credentials = new-object -typename System.Management.Automation.PSCredential -argumentlist "DOMAIN\Username",$password
    $output = start-process powershell -Credential $credentials -ArgumentList '-noexit','-File', 'C:\script\script2.ps1', $abc
    return $output
}

[string]$abc = $args

getUser($abc)

Write-host Output is $output

When I execute the script, the output is

Output is

And here is script2, which outputs the desired value to a cmd window instead of returning the value to script 1:

$userID = $NULL
$line_array = @()
$multi_array = @()
[hashtable]$my_hash = @{}

foreach ($i in $args) {
   $line_array+= $i.split(" ")
}

foreach ($j in $line_array) {
    $multi_array += ,@($j.split("="))
}

foreach ($k in $multi_array) {
    $my_hash.add($k[0],$k[1])
}

$Sender_IP = $my_hash.Get_Item("sender-ip")


<# Courtesy of http://blogs.technet.com/b/heyscriptingguy/archive/2012/02/19/use-powershell-to-find-last-logon-times-for-virtual-workstations.aspx#>

<# Gather information on the computer corresponding to $Sender_IP #>
$Win32OS = Get-WmiObject -Class Win32_OperatingSystem -ComputerName $Sender_IP

<# Determine the build number #>
$Build = $Win32OS.BuildNumber


<# Running Windows Vista with SP1 and later, i.e. $Build is greater than or equal to 6001 #>
if ($Build -ge 6001) {
    $Win32User = Get-WmiObject -Class Win32_UserProfile -ComputerName $Sender_IP
    $Win32User = $Win32User | Sort-Object -Property LastUseTime -Descending
    $LastUser = $Win32User | Select-Object -First 1
    $UserSID = New-Object System.Security.Principal.SecurityIdentifier($LastUser.SID)
    $userId = $UserSID.Translate([System.Security.Principal.NTAccount])
    $userId = $userId.Value
}

<# Running Windows Vista without SP1 and earlier, i.e $Build is less than or equal to 6000 #>
elseif ($Build -le 6000) {
    $SysDrv = $Win32OS.SystemDrive
    $SysDrv = $SysDrv.Replace(":","$")
    $ProfDrv = "\\" + $Sender_IP + "\" + $SysDrv
    $ProfLoc = Join-Path -Path $ProfDrv -ChildPath "Documents and Settings"
    $Profiles = Get-ChildItem -Path $ProfLoc
    $LastProf = $Profiles | ForEach-Object -Process {$_.GetFiles("ntuser.dat.LOG")}
    $LastProf = $LastProf | Sort-Object -Property LastWriteTime -Descending | Select-Object -First 1
    $userId = $LastProf.DirectoryName.Replace("$ProfLoc","").Trim("\").ToUpper()
}

else{
    $userId = "Unknown/UserID"
}


# Logic block to return the correct value
if ($userId -ne $NULL) {
    return "userId=" + $userId
}
elseif ($userID -eq $NULL)
{
    return "userId=" + $userId
}

I am willing to use other functions and cmdlets, but it is absolutely necessary that the script automatically runs in elevated mode because a third party program is calling script 1, which calls script 2, so script 2 needs to send value back to script 1, which goes to third party program.

(I posted updated question in a question, ProcessStartInfo and Process in PowerShell - Authentication Error).

Solution

You could make use of ProcessStartInfo and Process which would allow you to read the StandardOutput.

Here's an example of what you might do:

$startInfo = New-Object System.Diagnostics.ProcessStartInfo
$startInfo.FileName = "powershell.exe"
$startInfo.Arguments = "C:\script\script2.ps1"

$startInfo.RedirectStandardOutput = $true
$startInfo.UseShellExecute = $false
$startInfo.CreateNoWindow = $false
$startInfo.Username = "DOMAIN\Username"
$startInfo.Password = $password

$process = New-Object System.Diagnostics.Process
$process.StartInfo = $startInfo
$process.Start() | Out-Null
$standardOut = $process.StandardOutput.ReadToEnd()
$process.WaitForExit()

# $standardOut should contain the results of "C:\script\script2.ps1"
$standardOut