How to install older formula using Brew?

Question

Using the case of installing Python 2.7.9 instead of the latest 2.7.10, previously I could simply use brew versions python and see all of the versions of Python

Answer 1

Homebrew doesn't support installing formulas from git history, although it's possible. There are no python* formulas in the homebrew-versions tap because I think they would be a lot of work to maintain and don't provide the best possible user experience. pyenv is a great tool that solves a lot of the problems associated with keeping multiple pythons around. There's also a user-maintained tap with older Python versions; you could contribute a 2.7.9 formula there.