|  | # Flutter Attach | 
|  |  | 
|  | ## Overview | 
|  |  | 
|  | A Flutter-command that attaches to applications that have been launched | 
|  | without `flutter run` and provides a HotRunner (enabling hot reload/restart). | 
|  |  | 
|  | ## Usage | 
|  |  | 
|  | There are three ways for the attach command to discover a running app: | 
|  |  | 
|  | 1. If the platform is Fuchsia the module name must be provided, e.g. `$ | 
|  | flutter attach --module=mod_name`. This can be called either before or after | 
|  | the application is started, attach will poll the device if it cannot | 
|  | immediately discover the port | 
|  | 1. On Android and iOS, just running `flutter attach` suffices. Flutter tools | 
|  | will search for an already running Flutter app or module if available. | 
|  | Otherwise, the tool will wait for the next Flutter app or module to launch | 
|  | before attaching. | 
|  | 1. If the app or module is already running and the specific VM Service port is | 
|  | known, it can be explicitly provided to attach via the command-line, e.g. | 
|  | `$ flutter attach --debug-port 12345` | 
|  |  | 
|  | ## Source | 
|  |  | 
|  | See the [source](https://github.com/flutter/flutter/blob/master/packages/flutter_tools/lib/src/commands/attach.dart) for the attach command. |