mac之homebrew安装
通过homebrew可以管理众多开源软件的安装和卸载。使用homebrew可以非常容易的安装 os x中没有包含的unix工具包和语言包，比如wget;node;lua;rabbitmq;nginx等
安装
1.在终端运行命令
ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
第一次安装提示信息：
localhost:~ bobo$ /usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
==> This script will install:
/usr/local/bin/brew
xcode-select: note: no developer tools were found at '/Applications/Xcode.app', requesting install. Choose an option in the dialog to download the command line developer tools.
/usr/local/Homebrew
==> The following new directories will be created:
/usr/local/Cellar
/usr/local/Homebrew
/usr/local/Frameworks
/usr/local/bin
/usr/local/etc
/usr/local/include
/usr/local/lib
/usr/local/opt
/usr/local/sbin
/usr/local/share
/usr/local/share/zsh
/usr/local/share/zsh/site-functions
/usr/local/var
Press RETURN to continue or any other key to abort
当执行到fatal: unable to access 'https://github.com/Homebrew/brew/': Failed to connect to github.com port 443: Operation timed out
2.好吧，既然没有安装成功（可能有临时文件）那就卸载干净重新安装呗
执行卸载命令：
localhost:~ bobo$ /usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/uninstall)"
奶奶的，说什么没有找到改软件
Failed to locate Homebrew!
3.你既然说没有找到该软件（就是没有安装呗），那就再次执行安装命令呗
localhost:~ bobo$ /usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/uninstall)"
火大了！！！ 又提示我已经安装过啦 哼哼哼～
It appears Homebrew is already installed. If your intent is to reinstall you
should do the following before running this installer again:
ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/uninstall)"
The current contents of /usr/local are bin Cellar etc Frameworks Homebrew include lib opt sbin share var
4.没办法啊，去卸载干净再来吧。丧～
网上各种命令卸载都不好使，既然有安装的临时文件，那就各种删除临时文件。
依第一次安装新建的文件夹住要删除Cellar ; Frameworks ; Homebrew此三个文件
---> local ls -al
rm -rf Cellar Frameworks Homebrew
注：文件夹可能删除不了报“权限拒绝访问” ， 查看笔记命令（常用）
5.再次安装
localhost:~ bobo$ ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
-e:82: warning: Insecure world writable dir /usr/local/bin in PATH, mode 040777
==> This script will install:
/usr/local/bin/brew
/usr/local/share/doc/homebrew
/usr/local/share/man/man1/brew.1
/usr/local/share/zsh/site-functions/_brew
/usr/local/etc/bash_completion.d/brew
/usr/local/Homebrew
==> The following new directories will be created:
/usr/local/Cellar
/usr/local/Homebrew
/usr/local/Frameworks
Press RETURN to continue or any other key to abort
这次安装只新建了3个文件夹，就是之前删除的那三个。
继续往下执行，最后出现下面的提示表示安装成功
==> Installation successful!
==> Next steps
Run `brew help` to get started
Further documentation: https://git.io/brew-docs
==> Homebrew has enabled anonymous aggregate user behaviour analytics
Read the analytics documentation (and how to opt-out) here:
执行brew help ， 正常显示命令帮助，nice。
