Cocoapods版本更新

$ sudo gem update --system // 先更新gem，国内需要切换源

$ sudo gem install cocoapods // 安装cocoapods

$ pod setup

$ pod--version  //查看pod版本

Cocoapods版本回退

例：将版本1.0.1回退到版本0.39.0

1.删除pod

<1>$ which pod  //查看pod安装位置 /usr/username/bin/pod

<2>$ sudo rm -rf  /usr/username/bin/pod  //手动删除pod

2.移除RubyGems中的Cocoapods程序包

<1>查看gems中本地程序包

$ gem list

<2>删除cocoapods和cocoapods-core程序包

$ sudo gem uninstall cocoapods -v 1.0.1

$ sudo gem uninstall  cocoapods-core -v 1.0.1

输出成功后输出

Successfully uninstalled cocoapods-1.0.1

Successfully uninstalled cocoapods-core-1.0.1

<3>安装0.39.0版本的Cocoapods

$sudo gem install cocoapods -v 0.39.0