rmtoo is a free and open source requirements management tool.
rmtoo uses a different approach than most other requirements management tools: it comes as a command line tool which is optimized for handling requirements. The power of rmtoo lies in the fact that the development environment can handle the input and output files - there is no need for a special tool set environment.

Example: if you need to handle baselines (and there often is), rmtoo can be configured using a revision control system (e.g. git). The revision control system can handle different revisions, baselineing, tagging, branching and many other things extremely well - there is no reason to reinvent the wheel and making it less efficient.

rmtoo fits perfectly in a development environment using text editors and command line tools such as emacs, vi, eclipse, make, maven.

• Use simple text files as input - use your favorite editor
• Many different output formats and artifacts are supported:

• PDF - with links to dependent requirements
• HTML - also with links to dependent requirements
• Requirements dependency graph
• Requirement count history graph

• Fully integrated revision control system: git. Usages: history,
  statistics and baseline handling.
• Many different input and output modules.