I'm in a situation where I absolutely must use the specific version 2.5.1 of RabbitMQ (or any version 2.5.x should do really) and I can't find how to install it via Homebrew anywhere, can anyone provide good instructions as to how to get it?
(note that this answer is from 2014 and MAY no longer be relevant)
First, check whether version you need exists in homebrew
$ brew versions rabbitmq
Mine shows (... - skipped for readability):
...
2.5.1 git checkout 3630e1b Library/Formula/rabbitmq.rb
...
Then just checkout version you want (in your case 2.5.1):
git checkout 3630e1b Library/Formula/rabbitmq.rb
And finally install rabbitmq formula:
brew install rabbitmq