brew update 오류

Error: The /usr/local directory is not writable.

Even if this directory was writable when you installed Homebrew, other

software may change permissions on this directory. For example, upgrading

to OS X El Capitan has been known to do this. Some versions of the

"InstantOn" component of Airfoil or running Cocktail cleanup/optimizations

are known to do this as well.

이렇게 오류가 나는 경우가 있다ㅠ

sudo chown -R {name}:admin /usr/local

한 후에 brew update 한다!