You don't have write permissions

升级 cocoapods 报错
报错 You don't have write permissions for the /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/

用命令

sudo gem install -n /usr/local/bin cocoapods

安装或升级cocoapods 报错，You don't have write permissions for the /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/

解决办法：

用命令

brew install cocoapods  

进行升级或安装