A tiny script around github.com/wellington/go-libsass which is itself a binding for libsass, the C/C++ library, of the ruby on rails fame.
go-libsass doesn't provide a CLI, it is quite a PITA to vendor it (since it takes ages to build the lib), is handles SCSS over SASS by default, the documentation is pretty light. Meh.
Install: go get -u github.com/jeromenerf/gosass
Usage: gosass file.sass > file.css