Run a terminal command in a Mac app with Swift Xcode

Try this and let me know if it works. You should do this on a background thread using dispatch_async or NSOperationQueue. For more information on how to do stuff using Grand Central Dispatch read my post: http://manavgabhawala.me/#/blog/grand-central-dispatch

let task = NSTask()
task.launchPath = "/usr/sbin/sysctl"
task.arguments = ["-w", "net.inet.tcp.delayed_ack=0"]
let pipe = NSPipe()
task.standardOutput = pipe
task.standardError = pipe
task.launch()
task.waitUntilExit()
let data = pipe.fileHandleForReading.readDataToEndOfFile()
let output: String = NSString(data: data, encoding: NSUTF8StringEncoding) as! String

Also please can you update the question to include the exact error and the code you are using with NSTask if this doesn't work. Now this won't have the sudo effect that you wanted if you want that look at: https://developer.apple.com/library/mac/documentation/Security/Conceptual/authorization_concepts/01introduction/introduction.html which tells you about how to use sudo. For an unsandboxed app you could also do the same thing as above but change the launchPath to /bin/sh and then add an argument "-S" and also add the argument "/usr/sbin/sysctl". Then you can use standardInput to pipe in the password of the user who has root access. All password entry errors will come in the standard error pipe. Let me know if this works.