cocoapods 的使用，不知道怎么会出现问题

Question

为什么我输入sudo gem install cocoapods会输出这样的情况？求大神指点：
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Administrator. It usually boils down to these three things:

#1) Respect the privacy of others.
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Answer 1

输入gem install cocoapods为什么出现这样的情况：
ERROR: While executing gem ... (Gem::FilePermissionError)
You don't have write permissions for the /Library/Ruby/Gems/2.0.0 directory.