Here is everything you need to know about finding, downloading, and installing OS X 10.11 today.
sudo /Applications/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia --volume /Volumes/USB --application-path /Applications/Install\ OS\ X\ El\ Capitan.app --nointeraction os 10.11 download
For users already on 10.11 who need to reach the final stable version, the 10.11.6 Combo Update is available as a separate 1.5GB download. System Requirements for Installation Here is everything you need to know about