Download Mojave from the Mac App Store.
Use Disk Utility.app or
diskutil(1)to create a GUID Partition Map and format with Mac OS Extended (Journaled) on a target 8 GiB+ USB key.
Run these commands:
$ cd "/Applications/Install macOS Mojave.app/Contents/Resources" $ sudo ./createinstallmedia --volume /Volumes/YOURKEY \ --nointeraction --downloadassets $ echo The bird is the word, desu