安装CocoaPods
CocoaPods是使用Ruby语言所完成的一套管理程式，所以我们可以使用gem方式安装，安装主要程式需要root权限：
sudo gem install cocoapods`
输入密码
WARNING: Improper use of the sudo command could lead to data loss or the deletion of important system files. Please double-check your typing when using sudo. Type "man sudo" for more information. To proceed, enter your password, or type Ctrl-C to abort. Password:`
接下来就等它安装完成，撷取最后画面参考：
Successfully installed cocoapods-0.29.0 Parsing documentation for i18n-0.6.9 Installing ri documentation for i18n-0.6.9 Parsing documentation for multi_json-1.8.4 Installing ri documentation for multi_json-1.8.4 Parsing documentation for activesupport-3.2.16 unable to convert "\x80" from ASCII-8BIT to UTF-8 for lib/ active_support/values/unicode_tables.dat, skipping Installing ri documentation for activesupport-3.2.16 Parsing documentation for nap-0.6.0 Installing ri documentation for nap-0.6.0 Parsing documentation for json_pure-1.8.1 Installing ri documentation for json_pure-1.8.1 Parsing documentation for fuzzy_match-2.0.4 Installing ri documentation for fuzzy_match-2.0.4 Parsing documentation for cocoapods-core-0.29.0 Installing ri documentation for cocoapods-core-0.29.0 Parsing documentation for claide-0.4.0 Installing ri documentation for claide-0.4.0 Parsing documentation for cocoapods-downloader-0.3.0 Installing ri documentation for cocoapods-downloader-0.3.0 Parsing documentation for rake-10.1.1 Installing ri documentation for rake-10.1.1 Parsing documentation for colored-1.2 Installing ri documentation for colored-1.2 Parsing documentation for xcodeproj-0.14.1 Installing ri documentation for xcodeproj-0.14.1 Parsing documentation for cocoapods-try-release-fix-0.1.1 Installing ri documentation for cocoapods-try-release-fix-0.1.1 Parsing documentation for escape-0.0.4 Installing ri documentation for escape-0.0.4 Parsing documentation for open4-1.3.0 Installing ri documentation for open4-1.3.0 Parsing documentation for cocoapods-0.29.0 Installing ri documentation for cocoapods-0.29.0 16 gems installed`
以上结果代表已经安装完成，开始使用吧！