Creating Bootable El Capitan OSX Installer USB

[ZF]

Use Disk Utility and format the USB to GUID, MAC Journaled. Name it "Untitled".
sudo /Applications/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install\ OS\ X\ El\ Capitan.app --nointeraction