anchor.diff:  // prints out the rendered characters (ignoring colors and attributes).
   // This is probably most useful when stdin/stdout are redirected from/to files.
   
  +import 'dart:convert';
   import 'dart:core';
   import 'dart:io';
   
  
positive.code:     }
    }
  
    // TODO(vtl): Proper output format.
    for (var i = terminal.lines.length - 24; i < terminal.lines.length; i++) {
      var l = terminal.lines[i];
      for (var c in l.characters) {
        if (c == kTerminalUnfilledSpace) {
          c = 32;
        }
        stdout.writeCharCode(c);
      }
      stdout.writeCharCode(10);
    }
  }
  
negative.code:   for (int i = first_file; i < arguments.length; i++) {
      if (arguments[i] == '-') {
        while (true) {
          var c = stdin.readByteSync();
          if (c < 0) {
            break;
          }
  