cocoapods installation stuck on "Updating local specs repositories"

There's an known error with http://blog.cocoapods.org/Repairing-Our-Broken-Specs-Repository/

You can try to fix it by doing:

pod repo remove master
pod setup
pod install

For me it already happened a few times, always after cocoapods failing to contact github on a previous run if I'm not mistaken.

I solved by simply deleting the contents of ~/.cocoapods/repos. and running the pods again