安装方式：
/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
使用方式：
brew install xxx
比如：
安装git --- brew install git
安装maven --- brew install maven
安装/更新brew，报错：
Error: Could not link:
/usr/local/etc/bash_completion.d/brew
Please delete these paths and run `brew update`.
Error: Could not link:
/usr/local/share/zsh/site-functions/_brew
Please delete these paths and run `brew update`.
Error: Could not link:
/usr/local/share/man/man1/brew.1
Please delete these paths and run `brew update`.
Error: Could not link:
/usr/local/share/doc/homebrew
Please delete these paths and run `brew update`.
解决办法
rm -rf /usr/local/etc/bash_completion.d/brew
rm -rf /usr/local/share/zsh/site-functions/_brew
rm -rf /usr/local/share/man/man1/brew.1
rm -rf /usr/local/share/doc/homebrew
brew update
