1.檢視ruby版本
gem sources -l

列印
*** CURRENT SOURCES ***
https://rubygems.org/

      
2.替換ruby源
gem sources --remove https://rubygems.org/
gem sources -a https://gems.ruby-china.com/
    

3.安裝更新ruby新版本
sudo gem update --system
Password: 輸入密碼

列印資訊
Updating rubygems-update
Fetching: rubygems-update-2.7.7.gem (100%)
Successfully installed rubygems-update-2.7.7
Parsing documentation for rubygems-update-2.7.7
Installing ri documentation for rubygems-update-2.7.7
Installing darkfish documentation for rubygems-update-2.7.7
Done installing documentation for rubygems-update after 38 seconds
Parsing documentation for rubygems-update-2.7.7
Done installing documentation for rubygems-update after 0 seconds
Installing RubyGems 2.7.7

.
.
.報錯了 沒有解決 網說 ruby版本高於2.1.1就可以安裝cocoapods
ERROR:  While executing gem ... (Errno::EPERM)
    Operation not permitted @ rb_sysopen - /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/bin/gem
 

4. 安裝cocoapods
  sudo gem install -n /usr/local/bin cocoapods  
5. 輸入密碼
  Password:  
等待下載

6. 開始安裝
 pod setup  

7. 等待
//結果是綠色
CocoaPods 1.6.0.beta.2 is available.
To update use: `sudo gem install cocoapods --pre`
[!] This is a test version we'd love you to try.

For more information, see https://blog.cocoapods.org and the CHANGELOG for this version at https://github.com/CocoaPods/CocoaPods/releases/tag/1.6.0.beta.2

Setup completed