Create OS X El Capitan Installer iso image

create_install_iso.sh

#!/bin/sh

INSTALLERIMG="/Applications/Install OS X El Capitan.app/Contents/SharedSupport/InstallESD.dmg"
OUTDIR="/Users/$(whoami)/Desktop"
FILENAME="Install OS X El Capitan"

TMPIMG="/tmp/ElCapitan.sparseimage"
SOURCEDISK="/Volumes/InstallESD"
TARGETDISK="/Volumes/BaseSystem"

set -x
sudo -s
hdiutil attach "${INSTALLERIMG}" -noverify -nobrowse -mountpoint "${SOURCEDISK}"
hdiutil convert "${SOURCEDISK}/BaseSystem.dmg" -format UDSP -o "${TMPIMG}"
hdiutil resize -size 8g "${TMPIMG}"
hdiutil attach "${TMPIMG}" -noverify -nobrowse -mountpoint "${TARGETDISK}"
rm "${TARGETDISK}/System/Installation/Packages"
cp -rp "${SOURCEDISK}/Packages" "${TARGETDISK}/System/Installation/"
cp -rp ${SOURCEDISK}/BaseSystem* "${TARGETDISK}/"
cp -rp /System/Library/Kernels "${TARGETDISK}/System/Library/"
hdiutil detach "${SOURCEDISK}"
hdiutil detach "${TARGETDISK}"
hdiutil resize -size min "${TMPIMG}"
hdiutil convert "${TMPIMG}" -format UDTO -o "${OUTDIR}/${FILENAME}.cdr"
mv "${OUTDIR}/${FILENAME}.cdr" "${OUTDIR}/${FILENAME}.iso"
rm "${TMPIMG}"