brew update 时一些报错的解决方法

错误一：Error: Failed to update tap: homebrew/dupes

解决方案

brew untap homebrew/dupes
brew untap homebrew/versions
brew prune
brew tap homebrew/dupes
brew tap homebrew/versions

参考：https://github.com/Homebrew/homebrew-dupes/issues/384

错误二：Error: Permission denied - /usr/local/lib/dtrace/node.d

解决方案

brew link --overwrite node

sudo chown -R `whoami` /usr/local

参考：http://developpeers.com/blogs/fix-for-homebrew-permission-denied-issue...