diskimage-builder/elements/dib-init-system/install.d/20-install-init-scripts

#!/bin/bash
# Note that this relies on the detail that all elements share one dir inside
# the chroot. This will copy all the files that elements have added to
# element/static into the image. Mode, symlinks etc will be respected.

if [ ${DIB_DEBUG_TRACE:-1} -gt 0 ]; then
    set -x
fi
set -eu
set -o pipefail

scripts_dir="$(dirname $0)/../init-scripts/$DIB_INIT_SYSTEM/"
if [ -d "$scripts_dir" ]; then
    dest=
    case $DIB_INIT_SYSTEM in
        upstart) dest=/etc/init/ ;;
        systemd) dest=/usr/lib/systemd/system/ ;;
        sysv) dest=/etc/init.d/ ;;
    esac

    if [ -z "$dest" ]; then
        echo "ERROR: DIB_INIT_SYSTEM ($DIB_INIT_SYSTEM) is not an unknown type"
        exit 1
    fi
    cp -RP $scripts_dir. $dest || true
fi