brew install axel
curl https://developer.apple.com/videos/wwdc/2014/ | grep -ioI 'http.*._hd_.*dl=1">HD' | sed -e 's/\?dl=1">HD//g'| xargs -n1 axel -a -n 8
curl https://developer.apple.com/videos/wwdc/2014/ | grep -ioI 'http.*pdf?dl=1' | sed 's/\?dl=1//g' | xargs -n1 axel -a -n 4