MacをEl Capitanにして、brewがエラーになった時の対処法


brewのエラー内容

$ brew update
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. Some versions of the
"InstantOn" component of Airfoil are known to do this.

You should probably change the ownership and permissions of /usr/local
back to your user account.
  sudo chown -R $(whoami):admin /usr/local

解決方法

You should probably change the ownership and permissions of /usr/local
back to your user account.

権限を変更したほうがいいかもしれない。

参考:「You should probably」:したほうがいいかもしれない
http://ejje.weblio.jp/content/You+should+probably

と言われたので、
権限を変更。

$ sudo chown -R $(whoami):admin /usr/local

確認。

$ brew update
Already up-to-date.