How to display logs when I call the mina system command continuously in my sinatra app?

I want to call mina command in my sinatra app using `%x{mina ... }`.
But I can't get the log info as the deploying is going on. Instead I just can get all log after the deploying is over.

So is there a way to allow me to display the mina log in my sinatra app as the mina command is called? Or should I use another way instead of `%x{mina ...}`?
