MAC Error: The following directories are not writable by your user

有时候使用Homebrew安装应用的时候会出现：

Error: The following directories are not writable by your user:
/usr/local/share/man/man8
You should change the ownership of these directories to your user.
sudo chown -R $(whoami) /usr/local/share/man/man8

这是权限问题导致的，解决方式是收回权限，就可以正常的安装下载：

sudo chown -R `whoami`:admin /usr/local/bin
sudo chown -R `whoami`:admin /usr/local/share