docker-baseimage-ubuntu/root/etc/cont-init.d/99-custom-scripts

#!/usr/bin/with-contenv bash
# shellcheck shell=bash

# Directories
SCRIPTS_DIR_OLD="/config/custom-cont-init.d"
SERVICES_DIR_OLD="/config/custom-services.d"
SCRIPTS_DIR="/custom-cont-init.d"
SERVICES_DIR="/custom-services.d"

if [[ -z "$(/bin/ls -A ${SCRIPTS_DIR} 2>/dev/null)" ]] &&
    [[ -z "$(/bin/ls -A ${SCRIPTS_DIR_OLD} 2>/dev/null)" ]]; then
    echo "[custom-init] no custom files found, skipping..."
else
    # Make sure custom init directory exists and has files in it
    if [[ -e "${SCRIPTS_DIR}" ]] && [[ -n "$(/bin/ls -A ${SCRIPTS_DIR} 2>/dev/null)" ]]; then
        echo "[custom-init] files found, executing"
        for SCRIPT in "${SCRIPTS_DIR}"/*; do
            NAME="$(basename "${SCRIPT}")"
            if [[ -f "${SCRIPT}" ]]; then
                echo "[custom-init] ${NAME}: executing..."
                /bin/bash "${SCRIPT}"
                echo "[custom-init] ${NAME}: exited $?"
            elif [[ ! -f "${SCRIPT}" ]]; then
                echo "[custom-init] ${NAME}: is not a file"
            fi
        done
    fi

    if [[ -e "${SCRIPTS_DIR_OLD}" ]] && [[ -n "$(/bin/ls -A ${SCRIPTS_DIR_OLD} 2>/dev/null)" ]]; then
        echo "[custom-init] files found, executing"
        for SCRIPT in "${SCRIPTS_DIR_OLD}"/*; do
            NAME="$(basename "${SCRIPT}")"
            if [[ -f "${SCRIPT}" ]]; then
                echo "[custom-init] ${NAME}: executing..."
                /bin/bash "${SCRIPT}"
                echo "[custom-init] ${NAME}: exited $?"
            elif [[ ! -f "${SCRIPT}" ]]; then
                echo "[custom-init] ${NAME}: is not a file"
            fi
        done
    fi
fi

if [[ -n "$(/bin/ls -A "${SCRIPTS_DIR_OLD}" 2>/dev/null)" ]] ||
    [[ -n "$(/bin/ls -A "${SERVICES_DIR_OLD}" 2>/dev/null)" ]]; then
    cat << EOF | tee {${SCRIPTS_DIR_OLD}/README.txt,${SERVICES_DIR_OLD}/README.txt} 2>/dev/null
    ********************************************************
    ********************************************************
    *                                                      *
    *                         !!!!                         *
    * Custom scripts or services found in legacy locations *
    *                         !!!!                         *
    *    Please move your custom scripts and services      *
    *    to ${SCRIPTS_DIR} and ${SERVICES_DIR}     *
    *    respectively to ensure they continue working.     *
    *                                                      *
    *  Visit https://linuxserver.io/custom for more info.  *
    *                                                      *
    ********************************************************
    ********************************************************
EOF
fi
exit 0