Homebrew install specific version of formula?

Question

How do I install a specific version of a formula in homebrew? For example, postgresql-8.4.4 instead of the latest 9.0.

Answer 1

None of these really worked for my case (Python), so I'll add my 2 cents:

cd `brew --prefix`
git log Library/Formula/python.rb

Output looks like this:

commit 9ff2d8ca791ed1bd149fb8be063db0ed6a67a6de
Author: Dominyk Tiller 
Date:   Thu Jun 30 17:42:18 2016 +0100

    python: clarify pour_bottle reason

commit cb3b29b824a264895434214e191d0d7ef4d51c85
Author: BrewTestBot 
Date:   Wed Jun 29 14:18:40 2016 +0100

    python: update 2.7.12 bottle.

commit 45bb1e220341894bbb7de6fd3f6df20987dc14f0
Author: Rakesh 
Date:   Wed Jun 29 10:02:26 2016 +0530

    python 2.7.12

    Closes #2452.

    Signed-off-by: Tim D. Smith 

commit cf5da0547cd261f79d69e7ff62fdfbd2c2d646e9
Author: BrewTestBot 
Date:   Fri Jun 17 20:14:36 2016 +0100

    python: update 2.7.11 bottle.

...

I want version 2.7.11 so my hash is cf5da0547cd261f79d69e7ff62fdfbd2c2d646e9 (or cf5da05 for short). Next, I check out that version and install the formula python:

git checkout cf5da05
brew install python

Finally, clean up:

git checkout master