Mac安装homebrew和brew cask
在mac系统中，使用homebrew可以很方便的管理包.
官网提供的安装指令：/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
执行起来总是结果还是被卡在下载阶段，报错如下：LibreSSL SSL_read: SSL_ERROR_SYSCALL, errno 54
应该是这个资源访问有问题，那么我们可以尝试使用国内的镜像(中科大，清华)。
中科大源 https://mirrors.ustc.edu.cn/brew.git
一. 获取install文件
cd ~
curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install >> brew_install二.更改脚本中的资源链接，替换成中科大的镜像
编辑brew_install文件
#!/System/Library/Frameworks/Ruby.framework/Versions/Current/usr/bin/ruby
# This script installs to /usr/local only. To install elsewhere you can just
# untar https://github.com/Homebrew/brew/tarball/master anywhere you like or
# change the value of HOMEBREW_PREFIX.
HOMEBREW_PREFIX = "/usr/local".freeze
HOMEBREW_REPOSITORY = "/usr/local/Homebrew".freeze
HOMEBREW_CACHE = "#{ENV["HOME"]}/Library/Caches/Homebrew".freeze
HOMEBREW_OLD_CACHE = "/Library/Caches/Homebrew".freeze
#BREW_REPO = "https://github.com/Homebrew/brew".freeze
BREW_REPO = "https://mirrors.ustc.edu.cn/brew.git".freeze
#CORE_TAP_REPO = "https://github.com/Homebrew/homebrew-core".freeze
CORE_TAP_REPO = "https://mirrors.ustc.edu.cn/homebrew-core.git".freeze
注释掉BREW_REPO = "https://github.com/Homebrew/brew".freeze和CORE_TAP_REPO = "https://github.com/Homebrew/homebrew-core".freeze
修改为BREW_REPO = "https://mirrors.ustc.edu.cn/brew.git".freeze和CORE_TAP_REPO = "https://mirrors.ustc.edu.cn/homebrew-core.git".freeze
第三步，执行安装Homebrew脚本
/usr/bin/ruby brew_install然后可以看到这几句：
==> Tapping homebrew/core
Cloning into '/usr/local/Homebrew/Library/Taps/homebrew/homebrew-core'...
fatal: unable to access 'https://github.com/Homebrew/homebrew-core/': LibreSSL SSL_read: SSL_ERROR_SYSCALL, errno 54
Error: Failure while executing: git clone https://github.com/Homebrew/homebrew-core /usr/local/Homebrew/Library/Taps/homebrew/homebrew-core --depth=1
Error: Failure while executing: /usr/local/bin/brew tap homebrew/core出现这个原因是因为源不通，代码来不下来，解决方法就是更换国内镜像源：
执行下面这句命令，更换为中科院的镜像就下载成功了
git clone git://mirrors.ustc.edu.cn/homebrew-core.git/ /usr/local/Homebrew/Library/Taps/homebrew/homebrew-core --depth=1替换homebrew和homebrew-core的镜像地址为中科院的国内镜像
cd "$(brew --repo)"
git remote set-url origin https://mirrors.ustc.edu.cn/brew.git
cd "$(brew --repo)/Library/Taps/homebrew/homebrew-core"
git remote set-url origin https://mirrors.ustc.edu.cn/homebrew-core.git执行更新，成功：
brew update最后用这个命令检查无错误：
brew doctor这样就可以直接使用 brew 命令安装软件了。
第四步：安装brew cask
brew 安装完毕，安装brew cask
brew install caskroom/cask/brew-cask
出现error：
Error: Cask 'brew-cask' is unavailable: '/usr/local/Homebrew/Library/Taps/caskroom/homebrew-cask/Casks/brew-cask.rb' does not exist.
解决方法如下：
brew install brew-cask-completion
测试输入如下：
brew cask search qq
返回结果如下则成功：
==> Exact Match
qq
==> Partial Matches
qqbrowser qqinput qqlive qqmacmgr qqmusic替换brew cask的镜像地址为中科院的国内镜像
cd "$(brew --repo)"/Library/Taps/homebrew/homebrew-cask
git remote set-url origin https://mirrors.ustc.edu.cn/homebrew-cask.git
第五步. 替换 Bottles 源
Homebrew Bottles是Homebrew提供的二进制代码包，目前镜像站收录了以下仓库：
-
homebrew/homebrew-core
-
homebrew/homebrew-dupes
-
homebrew/homebrew-games
-
homebrew/homebrew-gui
-
homebrew/homebrew-python
-
homebrew/homebrew-php
-
homebrew/homebrew-science
-
homebrew/homebrew-versions
-
homebrew/homebrew-x11
替换方式如下
- bash（默认 shell）用户
echo 'export HOMEBREW_BOTTLE_DOMAIN=https://mirrors.ustc.edu.cn/homebrew-bottles' >> ~/.bash_profile
source ~/.bash_profile- 对于zsh用户
echo 'export HOMEBREW_BOTTLE_DOMAIN=https://mirrors.ustc.edu.cn/homebrew-bottles' >> ~/.zshrc
source ~/.zshrc
参考：
执行 brew install 命令长时间卡在 Updating Homebrew 的解决方法
https://learnku.com/articles/18908
Homebrew 中文主页
https://brew.sh/index_zh-cn.html
Homebrew Bottles 源使用帮助
http://mirrors.ustc.edu.cn/help/homebrew-bottles.html
Homebrew Cask 源使用帮助
http://mirrors.ustc.edu.cn/help/homebrew-cask.git.html
Homebrew Core 源使用帮助
http://mirrors.ustc.edu.cn/help/homebrew-core.git.html