PowerShell invoke shell command

Invoke-ShellCommand.ps1

function Invoke-ShellCommand
{
    param (
        $Command, 
        $Arguments,
        $WorkingDirectory
    )

    $psi = New-object System.Diagnostics.ProcessStartInfo 

    $psi.CreateNoWindow = $true
    $psi.UseShellExecute = $false
    $psi.RedirectStandardOutput = $true 
    $psi.RedirectStandardError = $true

    if ($WorkingDirectory)
    {
        $psi.WorkingDirectory = $WorkingDirectory
    }

    $psi.FileName = $Command
    $psi.Arguments = $Arguments

    $process = New-Object System.Diagnostics.Process 
    $process.StartInfo = $psi 
    [void]$process.Start()
    $stdout = $process.StandardOutput.ReadToEnd()
    $stderr = $process.StandardError.ReadToEnd()
    $process.WaitForExit() 
    $process.Close()

    return $stdout, $stderr
}