重新安装Brew

将MAC升级到mac os 12后，brew就不好用了。brew update直接卡死，试来试去不好用。

最后决定重装brew:

uninstall Brew：

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/uninstall.sh)"

 去Brew官网安装，使用VPN也是很慢。最后决定找到清华的镜像，从清华的镜像安装快捷方便，也不需要改Brew源。

https://mirrors.tuna.tsinghua.edu.cn/help/homebrew/

export HOMEBREW_BREW_GIT_REMOTE="https://mirrors.tuna.tsinghua.edu.cn/git/homebrew/brew.git"
export HOMEBREW_CORE_GIT_REMOTE="https://mirrors.tuna.tsinghua.edu.cn/git/homebrew/homebrew-core.git"
export HOMEBREW_BOTTLE_DOMAIN="https://mirrors.tuna.tsinghua.edu.cn/homebrew-bottles"

git clone --depth=1 https://mirrors.tuna.tsinghua.edu.cn/git/homebrew/install.git brew-install
/bin/bash brew-install/install.sh
rm -rf brew-install