First stab at "pub run" command.

sdk/lib/_internal/pub/lib/src/command.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library pub.command;
 
 import 'dart:async';
 import 'dart:math' as math;
 
 import 'package:args/args.dart';
 import 'package:path/path.dart' as path;
 
 import 'command/build.dart';
 import 'command/cache.dart';
 import 'command/deps.dart';
 import 'command/get.dart';
 import 'command/help.dart';
 import 'command/lish.dart';
 import 'command/list_package_dirs.dart';
+import 'command/run.dart';
 import 'command/serve.dart';
 import 'command/upgrade.dart';
 import 'command/uploader.dart';
 import 'command/version.dart';
 import 'entrypoint.dart';
 import 'exit_codes.dart' as exit_codes;
 import 'log.dart' as log;
 import 'system_cache.dart';
 import 'utils.dart';
 
@@ skipping 216 matching lines @@
 
 _initCommands() {
   var commands = {
     'build': new BuildCommand(),
     'cache': new CacheCommand(),
     'get': new GetCommand(),
     'help': new HelpCommand(),
     'deps': new DepsCommand(),
     'list-package-dirs': new ListPackageDirsCommand(),
     'publish': new LishCommand(),
+    'run': new RunCommand(),
     'serve': new ServeCommand(),
     'upgrade': new UpgradeCommand(),
     'uploader': new UploaderCommand(),
     'version': new VersionCommand()
   };
 
   for (var command in commands.values.toList()) {
     for (var alias in command.aliases) {
       commands[alias] = command;
     }
@@ skipping 35 matching lines @@
 
 /// Registers a [command] with [name] on [parser].
 void _registerCommand(String name, PubCommand command, ArgParser parser) {
   parser.addCommand(name, command.commandParser);
 
   // Recursively wire up any subcommands.
   command.subcommands.forEach((name, subcommand) {
     _registerCommand(name, subcommand, command.commandParser);
   });
 }