If you get the following error message after installing R on your mac:
$ R
dyld: Library not loaded: /usr/local/lib/gcc/5/libgfortran.3.dylib
Referenced from: /usr/local/Cellar/r/3.2.0_1/R.framework/Versions/3.2/Resources/lib/libR.dylib
Reason: image not found
Trace/BPT trap: 5
You’ll need to reinstall gcc with the –with-fortran option:
brew reinstall gcc5 --with-fortran