Recently, I had upgraded my Macintosh machine from version 10.8.5 to 10.9.2 (Mavericks) and immediately noticed some issues with it.
Notably, many of my binaries were no longer working that I had installed with
If you see these issues, yaou can fix it in one commnd...
brew update && brew upgrade
Once you do this, you'll notice that your binaries that you had installed with
brew now work again!