Contributions are very welcome, and should target Rust's master branch until the standard libraries are stabilized. You may claim an item on the to-do list by following these steps:
- Open an issue named "Implement [the utility of your choice]", e.g. "Implement ls"
- State that you are working on this utility.
- Develop the utility.
- Add integration tests.
- Add the reference to your utility into Cargo.toml and Makefile.
- Remove utility from the to-do list in the README.
- Submit a pull request and close the issue.
The steps above imply that, before starting to work on a utility, you should search the issues to make sure no one else is working on it.