❶：hdiutil create -o /tmp/Catalina -size 9000m -volname Catalina -layout SPUD -fs JHFS+

❷：hdiutil attach /tmp/Catalina.dmg -noverify -mountpoint /Volumes/Catalina

❸：sudo /Applications/Install\ macOS\ Catalina.app/Contents/Resources/createinstallmedia –volume /Volumes/Catalina –nointeraction

❹：hdiutil detach /volumes/Install\ macOS\ Catalina

❺：hdiutil convert /tmp/Catalina.dmg -format UDTO -o ~/Desktop/Catalina.cdr

❻：mv ~/Desktop/Catalina.cdr ~/Desktop/Catalina.iso

❼：rm /tmp/Catalina.dmg