I always seem to forget how to download the macOS version I need by the time I need it again, so here is a quick and nasty guide on how to download a properly signed *.dmg file to build a USB installer.
- The script below is just copy pasted from here: https://github.com/grahampugh/macadmin-scripts (This is a jacked up version of the original found here: https://github.com/munki/macadmin-scripts)
- Here is some nice documentation to use the script: https://derflounder.wordpress.com/2018/02/27/using-installinstallmacos-py-to-download-macos-high-sierra-installers/
If you don't want to download the tool or monkey around with permissions, give this a shot: (Provided you are dumb enough to pipe unknown code off the internet in sudo python of course):
sudo curl -s https://raw.githubusercontent.com/grahampugh/macadmin-scripts/master/installinstallmacos.py | sudo python - --help
If you're downloading an installer for your current machine, do the following: