Mac disk cleanup, because updating Xcode from the App Store needs at least 40GB of free disk space:
rm -rf $(brew --cache)
rm -fr ~/Library/Caches/com.spotify.client
http://hboon.com/iosdevnuggets/ios-dev-nugget-162-reclaim-disk-space-from-xcode-usage/
rm -rf ~/Library/Developer/Xcode/DerivedData/
rm -rf ~/Library/Developer/Xcode/iOS DeviceSupport/
yarn cache clean
rm -rf ~/.m2/repository
Takes about 3 mins
brew uninstall osgeo-*