Create Ubuntu Live CD ISO from scratch

#!/bin/sh
#
# IF YOUR COPY/ PASTING THIS SCRIPT PLEASE USE THE "RAW" SECTION
# OTHERWISE THIS SCRIPT WILL FAIL
#
apt-get install debootstrap syslinux squashfs-tools genisoimage openssh-server
if [ ! -f chroot/chroot.sh ]; then
    mkdir -p chroot
    mkdir -p image/casper
    mkdir -p image/isolinux
    mkdir -p image/install
    debootstrap precise chroot
fi
mount --bind /dev chroot/dev
cp /etc/hosts chroot/etc/hosts
sudo cp /etc/resolv.conf chroot/etc/resolv.conf
sudo cp /etc/apt/sources.list chroot/etc/apt/sources.list
mount --bind /dev chroot/dev
cat > chroot/chroot.sh  <<EOT
    #!/bin/sh
    mount none -t proc /proc
    mount none -t sysfs /sys
    mount none -t devpts /dev/pts
    export HOME=/root
    export LC_ALL=C
    apt-get update
    apt-get install --yes --force-yes dbus
    dbus-uuidgen > /var/lib/dbus/machine-id
    dpkg-divert --local --rename --add /sbin/initctl
    ln -s /bin/true /sbin/initctl
    apt-get --yes --force-yes upgrade
    apt-get install --yes --force-yes casper lupin-casper
    apt-get install --yes --force-yes discover laptop-detect os-prober
    apt-get install --yes --force-yes linux-generic
    apt-get install --yes --force-yes man-db
    echo "Customize your LiveCD now. Enter exit when done."
    bash -i
    rm /var/lib/dbus/machine-id
    rm /sbin/initctl
    dpkg-divert --rename --remove /sbin/initctl
    apt-get clean
    rm -rf /tmp/*
    rm /etc/resolv.conf
    umount -lf /proc
    umount -lf /sys
    umount -lf /dev/pts
EOT
chmod 755 chroot/chroot.sh
chroot chroot "/chroot.sh"
umount -lf chroot/dev
cp -v chroot/boot/vmlinuz-* image/casper/vmlinuz
cp -v chroot/boot/initrd* image/casper/initrd.lz
cp -v /usr/lib/syslinux/isolinux.bin image/isolinux/
cat > image/isolinux/isolinux.cfg <<EOT
DEFAULT live
LABEL live
kernel /casper/vmlinuz
append boot=casper persistent initrd=/casper/initrd.lz noprompt
EOT
chroot chroot dpkg-query -W --showformat='${Package} ${Version}\n' | tee image/casper/filesystem.manifest
cp -v image/casper/filesystem.manifest image/casper/filesystem.manifest-desktop
REMOVE='ubiquity ubiquity-frontend-gtk ubiquity-frontend-kde casper lupin-casper live-initramfs user-setup discover1 xresprobe os-prober libdebian-installer4'
for i in $REMOVE
do
        sudo sed -i "/${i}/d" image/casper/filesystem.manifest-desktop
done
[ -a image/casper/filesystem.squashfs ] && rm image/casper/filesystem.squashfs
mksquashfs chroot image/casper/filesystem.squashfs -e boot
touch image/ubuntu
mkdir image/.disk
cd image/.disk
touch base_installable
echo "full_cd/single" > cd_type
echo "Ubuntu Remix" > info
echo "http//your-release-notes-url.com" > release_notes_url
cd ../..
cd image
mkisofs -r -V "myBooty" -cache-inodes -J -l -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -o ../ubuntu-remix.iso .
cd ..