I worked on a similar project: a tool that (primarily) tees it's stdin to your tty before you decide how to continue your pipe[1], which is a little more general, though it's admittedly less polished or nice. I think there's an interesting space in making the process of writing commands more interactive, though doing that really well will involve an intelligent solution to the problem of commands with side effects.<p>[1] <a href="https://github.com/jkarni/extendp" rel="nofollow">https://github.com/jkarni/extendp</a>