I want to use "startosinstall" so that I can install macOS Catalina onto an external hard drive in order to preload MacOS onto multiple SSD's quickly.
I've researched into this and have found websites such as https://grahamrpugh.com/2018/03/26/reinstall-macos-from-system-volume.html which suggest using:
/Applications/Install\ macOS\ Catalina.app/Contents/Resources/startosinstall \ --applicationpath /Applications/Install\ macOS\ Catalina.app \ --agreetolicense --nointeraction --volume /Volumes/External\ Macintosh\ HD
I've tried running the above but have had no success and always find that I get this returned:
Usage: startosinstall Arguments --applicationpath, a path to copy of the OS installer application to start the install with. --license, prints the user license agreement only. --agreetolicense, agree to license the license you printed with --license. --rebootdelay, how long to delay the reboot at the end of preparing. This delay is in seconds and has a maximum of 300 (5 minutes). --pidtosignal, Specify a PID to which to send SIGUSR1 upon completion of the prepare phase. To bypass "rebootdelay" send SIGUSR1 back to startosinstall. --converttoapfs, specify either YES or NO on if you wish to convert to APFS. --installpackage, the path of a package (built with productbuild(1)) to install after the OS installation is complete; this option can be specified multiple times. --eraseinstall, Erase all volumes and install to a new one. Optionally specify the name of the new volume with --newvolumename. --newvolumename, the name of the volume to be created with --eraseinstall. --usage, prints this message. Example: startosinstall --converttoapfs YES
but can't seem to actually get anything to run.
If anyone could provide me with some working code or show me how to solve this problem, I would be eternally grateful.
Thanks for your help