To ensure a high-quality, safe file, use the official links provided by Apple. Other third-party sources may contain malware or corrupted data.
.app file to your Applications folder.https://support.apple.com/... and redirects to the App Store.hdiutil create -o /tmp/ElCapitan -size 6g -layout SPUD -fs HFS+J
hdiutil attach /tmp/ElCapitan.dmg -noverify -mountpoint /Volumes/ElCapitan
sudo /Applications/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia --volume /Volumes/ElCapitan --applicationpath /Applications/Install\ OS\ X\ El\ Capitan.app --nointeraction
hdiutil detach /Volumes/Install\ OS\ X\ El\ Capitan
hdiutil convert /tmp/ElCapitan.dmg -format UDTO -o /tmp/ElCapitan
mv /tmp/ElCapitan.cdr ~/Desktop/ElCapitan.iso
shasum -a 256 ~/Desktop/ElCapitan.iso