Since today is the release of macOS Monterey, I figured I’d post a quick one-liner (well, really two one-liners) to make a macOS Monterey install USB drive.

1. Download the full installer for macOS 12.0.1
   softwareupdate --fetch-full-installer 12.0.1

2. Once downloaded, we need to run the createinstallmedia command to copy the data to an external drive that will contain the bootable USB installer. (It’s assumed you already have a partition created for this, but please note, this command will format the partition and you will lose any data on the partition).
   sudo /Applications/Install\ macOS\ Monterey.app/Contents/Resources/createinstallmedia --volume /Volumes/MontereyInstaller/ --nointeraction