"It's like script/console in Rails or merb -i in Merb, but for any app built on Rack. You can use it to load application environment for Rails, Merb, Sinatra, Camping, Ramaze or your own framework provided there is config.ru file in app's root directory /.../ It loads whole application environment like Rack web server, but instead of running the app it starts irb session. Additionally it exposes $rack variable which allows you to make simulated HTTP requests to your app.".
I'm aware of racksh but it's not sinatra-specific. It has no knowledge of a sinatra app and thus can't give you sinatra-specific goodies that tux does: metrics for your sinatra app (routes + settings) and commandline interaction with your helpers and view rendering
Some people are incredibly stupid when choosing project names, playing on cute third or fourth meanings of common words that have almost nothing to do with their projects or choosing names used by similar but unrelated projects, making it almost impossible to search for specific information. The "best" project name I have seen so far is "kiwi". Among others, there are two independent projects kiwi from different institutes in the Stanford CS department, the OpenSUSE build manager and an EU semantic web project (and of course loads of non computer related project of every kind from New Zealand). Gah.
"It's like script/console in Rails or merb -i in Merb, but for any app built on Rack. You can use it to load application environment for Rails, Merb, Sinatra, Camping, Ramaze or your own framework provided there is config.ru file in app's root directory /.../ It loads whole application environment like Rack web server, but instead of running the app it starts irb session. Additionally it exposes $rack variable which allows you to make simulated HTTP requests to your app.".