With the recent release of Sencha CMD 4.0, we get the “somewhat” undocumented watch command (only reference I’ve found to it was in the beta1 release notes). This command will watch your file system for changes and automatically rebuild the parts of your app that have changed and need to be rebuilt. There is no longer a need to switch back to the terminal window and run the refresh/build commands. It’s all handled for you. Read on to see an example.