I need to install sencha touch 2.1 on my mac but I can\'t…
i follow this guide
http://www.sencha.com/learn/getting-started-with-sencha-touch-2
The Sencha Touch Sdk contains only the classes which contains the framework, plus examples and docs. If you want to generate an app, compile it, etc. using the Sencha command from a terminal, you need to install the Sencha Cmd then. That's a different product.
You can read more at the following guide: http://docs.sencha.com/touch/2-1/#!/guide/command
And download the latest version from here: http://www.sencha.com/products/sencha-cmd/download