[pod install] error: cannot open .git/FETCH_HEAD: Permission denied

pod install
Analyzing dependencies
[!] Pod::Executable pull

error: cannot open .git/FETCH_HEAD: Permission denied

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http://stackoverflow.com/questions/16049335/cocoapods-pod-install-permission-denied

I solve this problem by running the following command:

sudo chown -R username.groupname ~/Library/Caches/CocoaPods

and

sudo chown -R username.groupname ~/.cocoapods

Please replace username and groupname with your Mac login username/groupname.

或者 

Will-mini:Caches willbin$ sudo chown -R $USER ~/Library/Caches/CocoaPods/
Will-mini:Caches willbin$ sudo chown -R $USER ~/.cocoapods