Started working with Homebrew recently instead of Macports to install third party packages on OSX. Homebrew comes with a doctor command that lets you know any conflicts that may cause it to not function properly. Short of it all is that Homebrew told me I needed to modify my path to make sure the /usr/local/bin is before /usr/bin. But where is the path defined on OSX? it is in /etc/paths (at least on OSX Mountain Lion). This file is a list of paths, each defined on a separate line which also specified their order. In order to update it run:

sudo vi /etc/paths

here is what mine looks like:

/usr/local/bin
/usr/bin
/bin
/usr/sbin
/sbin

read more