Pete Hinchley: Make a Bootable El Capitan Installation USB Stick

So you've downloaded El Capitan from the App Store to your Mac. The installer is sitting in your Applications folder. And now you want to create a bootable USB stick that can be used to perform a clean installation of the operating system on another system. Here's what you do.

• Insert a USB stick into your Mac. It will be trashed, so make sure you take a copy of anything important.

• From Terminal, list the connected disks, and identify the path to the USB stick:

   diskutil list

• Format the disk and set a label of Untitled (replace /dev/disk4 with the relevant path identified during the previous step).

  sudo diskutil eraseDisk JHFS+ Untitled /dev/disk4

• Copy El Capitan to the USB stick, and make it bootable:

   sudo /Applications/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install\ OS\ X\ El\ Capitan.app --nointeraction

• Plug the USB stick into another Mac, power it on whilst holding down the Option key, and proceed with the installation.