Apple - How to set gcc 4.8 as default gcc compiler

Assuming you're using bash (it's the default), then you can add /usr/local/bin as your top priority in PATH like this:

echo "PATH=\"/usr/local/bin:$PATH\"" >> ~/.bash_profile

This will ensure that /usr/local/bin is checked before all other areas of your path. Then just start a new terminal session to load the new variable.

Another way to do this:

  cd /usr/bin
  rm cc gcc c++ g++
  ln -s /usr/local/bin/gcc-4.8 cc
  ln -s /usr/local/bin/gcc-4.8 gcc
  ln -s /usr/local/bin/c++-4.8 c++
  ln -s /usr/local/bin/g++-4.8 g++

Thanks to you all for your help. I ended up just creating aliases within ~/.bash_profile as follows:

alias gcc='gcc-4.8'
alias cc='gcc-4.8'
alias g++='g++-4.8'
alias c++='c++-4.8'

The answer from Lynken is very helpful, but I adapted it with aliases since that's easier for me to undo if necessary.

Specifically, if PATH is set such that /usr/local/bin (where brew puts the link to gcc 4.8) appears before appears /usr/bin (where gcc is linked by default), then creating links as Lyken suggested within /usr/local/bin should theoretically work for me. In practice, it doesn't for some reason -- failing with a linker error and aliases work around that error without me needing to solve that issue, too.

The other benefit of aliases is that I'm not having to link which I want homebrew to handle and not have to compete with that tool for which version of gcc is linked in /usr/local

I use to gcc-4.8:

export CC=/usr/local/bin/gcc

export CXX=/usr/local/bin/g++

export CPP=/usr/local/bin/cpp

export LD=/usr/local/bin/gcc

alias c++=/usr/local/bin/c++

alias g++=/usr/local/bin/g++

alias gcc=/usr/local/bin/gcc

alias cpp=/usr/local/bin/cpp

alias ld=/usr/local/bin/gcc

alias cc=/usr/local/bin/gcc

and back to apple gcc:

export CC=/usr/bin/gcc

export CXX=/usr/bin/g++

export CPP=/usr/bin/cpp

export LD=/usr/bin/ld

alias c++=/usr/bin/c++

alias g++=/usr/bin/g++

alias gcc=/usr/bin/gcc

alias cpp=/usr/bin/cpp

alias cc=/usr/bin/gcc

alias ld=/usr/bin/ld

or put it in file and then: source <file>