gb is a proof of concept replacement build tool for the Go programming language.
I gave a talk about gb and the rational for its creation at GDG Berlin in April 2015, video and slides.
gb operates on the concept of a project. A gb project is a workspace for all the Go code that is required to build your project.
A gb project is a folder on disk that contains a subdirectory named src/. That's it, no environment variables to set. For the rest of this document we'll refer to your gb project as $PROJECT.
You can create as many projects as you like and move between them simply by changing directories.
go get github.com/constabulary/gb/...
gb has its own site, getgb.io, head over there for more information.