问题
打算使用 CocoaPods 安装一些第三方库。当执行 pod install 命令时报如下错误：
-bash: /usr/local/bin/pod: /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/bin/ruby: bad interpreter: No such file or directory
问题分析
可能Mac系统版本更新导致，那么重新安装镜像试一下
处理
1.首先执行如下命令查看所有 gem 源，检查是否是最新的：
gem sources -l
输出结果
*** CURRENT SOURCES ***
2.由于 RubyGems 镜像服务域名变更（后缀由之前的 org 改成 com），我们先执行如下命令将当前的 gem 源删除：
gem sources --remove https://gems.ruby-china.org/
输出结果
source https://gems.ruby-china.org/ not present in cache
3.添加新的 gem 源
gem sources -a https://gems.ruby-china.com
输出结果
https://gems.ruby-china.com added to sources
4.更新 gem
sudo gem update --system
输出结果
Latest version already installed. Done.
5.升级 CocoaPods
sudo gem install -n /usr/local/bin cocoapods --pre
输出结果
Done installing documentation for concurrent-ruby, i18n, thread_safe, tzinfo, activesupport, nap, fuzzy_match, httpclient, algoliasearch, ffi, ethon, typhoeus, netrc, cocoapods-core, claide, cocoapods-deintegrate, cocoapods-downloader, cocoapods-plugins, cocoapods-search, cocoapods-stats, cocoapods-trunk, cocoapods-try, molinillo, atomos, colored2, nanaimo, xcodeproj, escape, fourflusher, gh_inspector, ruby-macho, cocoapods after 42 seconds
32 gems installed
6.更新本地仓库
pod repo update
7.执行 pod install 不再报错了。
pod install
输出结果
Pod installation complete! There are 5 dependencies from the Podfile and 5 total pods installed.