cocoapod 更新 pod 时报错 While execut

参考链接在这里：我是链接

执行 pod update 命令时报错：

ERROR: While executing gem ... (Gem::FilePermissionError)

You don't have write permissions for the /usr/bin directory.

修改了权限后还是失败，试试这个命令

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