Create OSX installer ISO file (example for High Sierra)

createOSXInstallerIso

#!/usr/bin/env bash

# Create OSX Installer ISO.
# 2017 robertoschwald 
# https://gist.github.com/robertoschwald/7f9eadf78739128ea1fb7a32c0472e1c

installer_path=/Applications/Install\ macOS\ High\ Sierra.app
installer_mountpoint=/Volumes/Install\ macOS\ High\ Sierra

echo "Creating Install ISO"

if [ ! -d "${installer_path}" ]; then
	echo "Please download OSX to ${installer_path} from Appstore, first"
	exit 1
fi

echo "Are you sure?"
read yn
if [ ${yn} != "y" ]; then
	echo "Aborting."
	exit 1
fi

echo " "
echo "Creating temporary install DMG file.."
hdiutil create -o /tmp/HighSierra.cdr -size 5130m -layout SPUD -fs HFS+J
if [ ! -f /tmp/HighSierra.cdr.dmg ]; then
	echo "Failed to create temporary DMG file /tmp/HighSierra.cdr.dmg"
	exit 1
fi

echo " "
echo "Mounting /tmp/HighSierra.cdr.dmg"
hdiutil attach /tmp/HighSierra.cdr.dmg -noverify -mountpoint /Volumes/install_build
if [ $? != 0 ]; then
	echo "Failed to mount temporary DMG file /tmp/HighSierra.cdr.dmg"
	exit 1
fi

echo " "
echo "Creating install DMG"
sudo "${installer_path}"/Contents/Resources/createinstallmedia --volume /Volumes/install_build
if [ ! -f /tmp/HighSierra.cdr.dmg ]; then
	echo "Failed to find /tmp/HighSierra.cdr.dmg"
	exit 1
fi

if [ -d "${installer_mountpoint}" ]; then
	echo "Unmounting ${installer_mountpoint}"
	umount "${installer_mountpoint}"
	if [ $? != 0 ]; then
		echo "Failed to unmount installer mount point ${installer_mountpoint}"
		exit 1
	fi
	sleep 3
fi

echo " "
echo "Moving dmg to ~/Desktop/InstallSystem.dmg"
cp /tmp/HighSierra.cdr.dmg ~/Desktop/InstallSystem.dmg # copy, not mv, as some process could have locked the file
rm -rf /tmp/HighSierra.cdr.dmg

echo " "
echo "Convert ~/Desktop/InstallSystem.dmg to HighSierra.iso"
hdiutil convert ~/Desktop/InstallSystem.dmg -format UDTO -o ~/Desktop/HighSierra.iso
if [ ! -f ~/Desktop/HighSierra.iso.cdr ]; then
	echo "Failed to create ~/Desktop/HighSierra.iso.cdr"
	exit 1
fi

mv ~/Desktop/HighSierra.iso.cdr ~/Desktop/HighSierra.iso

if [ -f ~/Desktop/InstallSystem.dmg ]; then
	rm ~/Desktop/InstallSystem.dmg
fi

echo "You find the iso on ~/Desktop/HighSierra.iso"