High Sierra installer on Sierra or earlier: sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia -volume /Volumes/MyVolume -applicationpath /Applications/Install\ macOS\ High\ Sierra.app High Sierra installer on High Sierra: sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia -volume /Volumes/MyVolume Mojave installer on Sierra or earlier: sudo /Applications/Install\ macOS\ Mojave.app/Contents/Resources/createinstallmedia -volume /Volumes/MyVolume -applicationpath /Applications/Install\ macOS\ Mojave.app
Mojave installer on Mojave or High Sierra: sudo /Applications/Install\ macOS\ Mojave.app/Contents/Resources/createinstallmedia -volume /Volumes/MyVolume
Take note that the commands differ slightly for creating Mojave and High Sierra installers on older versions of macOS. Just replace the MyVolume portion of the command with the name you gave your drive in the Disk Utility step above. Terminal is the easiest way to create your bootable USB drive.
