Cocoapods 版本升级

和往常一样使用 Cocoapods ，执行命令：

$ pod install

#输出信息
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/dependency.rb:296:in `to_specs': Could not find 'cocoapods' (>= 0) among 59 total gem(s) (Gem::LoadError)
    from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/dependency.rb:307:in `to_spec'
    from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_gem.rb:47:in `gem'
    from /usr/local/bin/pod:22:in `<main>'

查看 Ruby 版本：

$ ruby -v
ruby 2.2.3p173 (2015-08-18 revision 51636) [x86_64-darwin14]

看来是升级 Ruby 2.2.3 导致的问题，更新下 Cocoapods 即可，更新步骤：

1、 更新 gem ，国内需切换 gem source

$ sudo gem update --system

• 切换 gem source

$ gem sources --add https://ruby.taobao.org/ --remove https://rubygems.org/

$ gem sources -l
*** CURRENT SOURCES***

https://ruby.taobao.org

2、 安装 cocoapods

$ sudo gem install cocoapods
$ pod setup

和安装过程是一样的，再次查看 pod 版本：

$ pod --version

0.39.0