codemetre allows you to compare different versions of your software project, determining how and how much source files have changed. It currently recognizes both source code and comments from Ada, Bash shell, C, Eiffel, SQL, and more. It can also provide you with metrics on any single snapshot of your project.
PeRKy is computer software dedicated to management of software requirements with any Source Control Manager (abbreviated SCM) as a storage layer, based on a simple principle: 1 file per requirement. PeRKy helps developers keep documentation in sync with their code by using the same tools for both. It also integrates notions of distributed development, and thus highly limits the risk of encountering conflicts when merging branches of development.