$ brew doctor Warning: Broken symlinks were found. Remove them with `brew prune`: /usr/local/bin/c++-4.9 /usr/local/bin/cpp-4.9 /usr/local/bin/g++-4.9 /usr/local/bin/gcc-4.9 /usr/local/bin/gcc-ar-4.9 /usr/local/bin/gcc-nm-4.9 /usr/local/bin/gcc-ranlib-4.9 /usr/local/bin/gcov-4.9 /usr/local/bin/gfortran /usr/local/bin/gfortran-4.9 /usr/local/bin/github /usr/local/bin/x86_64-apple-darwin13.2.0-c++-4