curl -o ~/Downloads/InstallMacOSX.dmg http://updates-http.cdn-apple.com/2019/cert/061-41343-20191023-573f2b24-47ef-4b3f-9f47-79d7241b16ab/InstallMacOSX.dmg
While Apple has tried to bury this installer, it remains legally available to anyone with an Apple ID history. Avoid sketchy third-party forums; use the App Store hidden link or a verified checksum download. Mac Os X El Capitan 10.11.6 Installer Dmg Download
El Capitan remains a vital piece of software history because it serves as a critical : curl -o ~/Downloads/InstallMacOSX