Run `./installinstallmacos.py --help` to see the available options.
The tool assembles "Install macOS" applications by downloading the packages from Apple's softwareupdate servers and then installing them into a new empty disk image.
If `/usr/bin/installer` returns errors during this process, it can be useful to examine `/var/log/install.log` for clues.
Since it is using Apple's installer, any install check or volume check scripts are run. This means that you can only use this tool to create a diskimage containing the versions of macOS that will run on the exact machine you are running the script on.
For example, to create a diskimage containing the version 10.13.6 that runs on 2018 MacBook Pros, you must run this script on a 2018 MacBook Pro, and choose the proper version.
Typically "forked" OS build numbers are 4 digits, so when this document was last updated, build 17G2208 was the correct build for 2018 MacBook Pros; 17G65 was the correct build for all other Macs that support High Sierra.
If you attempt to install an incompatible version of macOS, you'll see an error similar to the following:
```
Making empty sparseimage...
installer: Error - ERROR_B14B14D9B7
Command '['/usr/sbin/installer', '-pkg', './content/downloads/07/20/091-95774/awldiototubemmsbocipx0ic9lj2kcu0pt/091-95774.English.dist', '-target', '/private/tmp/dmg.Hf0PHy']' returned non-zero exit status 1
Use a compatible Mac or select a different build compatible with your current hardware and try again. You may also have success running the script in a VM; the InstallationCheck script in versions of the macOS installer to date skips the checks (and returns success) when run on a VM.
Graham Pugh has a fork with a lot more features and bells and whistles. Check it out if your needs aren't met by this tool. https://github.com/grahampugh/macadmin-scripts
This script was used to extract the firmware updaters from early High Sierra installers and make a standalone installer package that could be used to upgrade Mac firmware before installing High Sierra via imaging.
Later High Sierra installer changes have broken this script; since installing High Sierra via imaging is not recommended or supported by Apple and several other alternatives are now available, I don't plan on attempting to fix or upgrade this tool.