I have a simple NSButton function executing a 'ls -la' command:
@IBAction func Convert(_ sender: NSButton) {
    let path = "/bin/ls"
    let arguments = ["-la"]
    sender.isEnabled = false
    let task = Process.launchedProcess(launchPath: path, arguments: arguments)
    task.waitUntilExit()
    sender.isEnabled = true
}
I need the stdout in my NSScrollView:
@IBOutlet weak var Output: NSScrollView!