Blocking and retrieving user keyboard input

I'm implementing my own version of a command line interface/terminal, but I'm struggling with how I would block/wait for user input. My gut tells me I should be trying to emulate something along the lines of .NET's Console.Read(), which returns a string with the user's input.

I've got a solution that works in what feels like a really round-about way. I'm using coroutines to wait for user input, and when return is pressed, I set a private variable with the user input, and then access it after I call my Read() coroutine. It works, but it just feels messy. I'm trying to figure out if this is a reasonably acceptable way of doing things.

Here's the gist of what I'm doing

 private string input;
 private string keyboardInput;
 
 private bool returnPressed = false;
 
 void Start () 
 {
     //initialize stuff
     StartCoroutine(StartGame());
 }
 
 void Update() 
 {
     //Capture keyboard input (abbreviated for clarity)
     keyboardInput += Input.inputString;
 }
 
 private IEnumerator StartGame()
 {
     WriteSomeText("Enter a value: ");
     yield return StartCoroutine(Read());
     string userInput = input;
 
     //Do stuff
 
     WriteSomeText("Enter another value: ");
     yield return StartCoroutine(Read());
     string userInput = input;
 
     //Do more stuff
 }
 
 private IEnumerator Read()
 {
     input = "";
     keyboardInput = "";
 
     while(!returnPressed)
     {
         if(Input.GetKeyDown(KeyCode.Return))
         {
             returnPressed = true;
             input = keyboardInput;
         }
         yield return 0;
     }
 
     returnPressed = false;
 }