Synchronously get a line of user input from the command line console (stdin). Using synchronous I/O in the console can greatly simplify your program.

gistfile1.dart

import "dart:io";

void main() {
  // get user input using synchronous I/O
  String input = stdin.readLineSync();
  
  // get user input and convert to lowercase
  String inputLC = stdin.readLineSync().toLowerCase();

  print(input);
  print(inputLC);
}