Like Start-Process, but without files

Invoke-Process.ps1

function Invoke-Process {
    <#
    .SYNOPSIS
        Invokes a process, collecting the output

    .DESCRIPTION
        Invokes the process of the executable that is passed in using the command line arguments that are passed in

    .EXAMPLE
        Invoke-Process "C:\Program Files\7-Zip\7z.exe" 'x C:\temp -oC:\temp\path'
        Invokes 7zip with the x (extract) option, a path, and the -o (output) path

    .LINK
        Start-Process
    #>

    [CmdletBinding()]
    [OutputType([System.Diagnostics.Process], [String])]    
    param(
        # Full path to the process exe
        [Parameter(Mandatory, Position = 0)]
        [ValidateNotNullOrEmpty()]
        [ValidateScript( {Get-Command $_ -ErrorAction Stop; $True})]
        [Alias("PSPath", "FilePath")]
        [string]$ExePath,

        # Run processes in the current window
        [switch]$NoNewWindow,

        # Output the process object INSTEAD OF its output
        # If set, you are responsible to read the StandardInput and StandardError streams
        [switch]$Passthru,

        # Waits for the process to exit before continuing
        [int32]$TimeOut = [int32]::MaxValue,

        # The working directory to run the process in (defaults to PowerShell's current FileSystem location)
        [string]$WorkingDirectory = $((Get-Location -PSProvider FileSystem).Path),

        # Command Line Arguments
        [Parameter(ValueFromRemainingArguments)]
        [ValidateNotNullOrEmpty()]
        [string[]]$Arguments
    )
    # Future Work: Add a way to pass strings for the StandardInput stream
    #              Add a way to specify exit codes that are acceptable
    #              Make the event handlers stream output to the console

    $StartInfo = [System.Diagnostics.ProcessStartInfo]$ExePath
    $StartInfo.CreateNoWindow = $NoNewWindow
    $StartInfo.RedirectStandardError = $true
    $StartInfo.RedirectStandardOutput = $true
    $StartInfo.WorkingDirectory = $WorkingDirectory
    $StartInfo.Arguments = $Arguments -join " "
    $StartInfo.UseShellExecute = $false

    $Process = [System.Diagnostics.Process]::new()
    $Process.StartInfo = $StartInfo
    $null = Register-ObjectEvent -InputObject $Process -EventName OutputDataReceived -Action {if ($EventArgs.Data) {[String[]]$Event.MessageData += $EventArgs.Data}} -MessageData $ProcessOutput
    $null = Register-ObjectEvent -InputObject $Process -EventName ErrorDataReceived -Action {if ($EventArgs.Data) {[String[]]$Event.MessageData += $EventArgs.Data}} -MessageData $ProcessErrors
    $Process.Start() | Out-Null

    $Process.BeginOutputReadLine()
    $Process.BeginErrorReadLine()

    if (-not $Process.WaitForExit($TimeOut)) {
        Write-Error "Process [$($ExePath)] has timed out after [$([TimeSpan]::FromMilliseconds($TimeOut))]"
    }

    if ($Passthru) {
        $Process
        if ($Process.ExitCode -ne 0) {
            Write-Error "'$($ExePath) $($Arguments -join " ")' returned $($Process.ExitCode)."
        }
        return
    }

    # Normalize empty lines to only have one empty line together
    $ProcessOutput -replace "[\r\n]{3,}", "`n`n" -split "\r?\n"
    if ($ProcessErrors) {
        # In errors write one error for each block of lines in a message
        foreach ($message in $ProcessErrors -replace "[\r\n]{3,}", "`n`n" -split "\r?\n[\r\n]+") {
            Write-Error "$($ExePath): $($message)"
        }
    }

    if ($Process.ExitCode -ne 0) {
        Write-Error "'$($ExePath) $($Arguments -join " ")' returned $($Process.ExitCode)."
    }

}