hdiutil create -o /tmp/HighSierra -size 8000m -volname HighSierra -layout SPUD -fs HFS+J Use code with caution.
A Mac has to be 64-bit to run El Capitan, or anything beyond 10.7 (Lion). Apple Support Community OS X El Capitan | Specs, reviews and EoL info - InvGate reviews and EoL info - InvGate