In a system shell, issue the following command:
brew update
You can install MongoDB via brew with several different options. Use one of the following operations:
To install the MongoDB binaries, issue the following command in a system shell:
brew install mongodb
To build MongoDB from the source files and include TLS/SSL support, issue the following from a system shell:
brew install mongodb --with-openssl
To install the latest development release for use in testing and development, issue the following command in a system shell:
brew install mongodb --devel
原文：http://www.cnblogs.com/sban/p/4783194.html