If you don't know about it yet,Yeoman is a scaffolding tool for web developpers. It provides a generator ecosystem , you can usually run those generators with the yo CLI command.
Yeoman UI is a work in progress which allows you to access this ecosystem through a very light web app instead of the CLI. To tell the truth, I like CLI and I started this project not for making a CLI alternative but as need for a bigger project.
# First install the app
npm install && bower install
# Then run it
node index.js
# or with nodemon...
nodemon
Then you should go to http://localhost:3000/
Technically, Yeoman made this rather easy thanks to its great documentation and the adapter pattern. All the scaffolding part happens on the server side through Yeoman's API, not a shell execution. The client side is only doing the prompt interface which transit via WebSocket.
For now, once the project is scaffolded in a dist folder, it is compressed as a zip archive and send to the client. Also for now, no dependency (npm nor bower) is installed as npm should run on the final host system. Ideally, bower could be run but Yeoman doesn't expose distinct API between them.