config.json

{
  "name": "Hello World",
  "version": "1",
  "slug": "hello_world",
  "description": "My first real add-on!",
  "startup": "application",
  "boot": "auto",
  "options": {},
  "schema": {}
}

Dockerfile

ARG BUILD_FROM
FROM $BUILD_FROM

ENV LANG C.UTF-8

# Copy data for add-on
COPY run.sh /
RUN chmod a+x /run.sh

CMD [ "/run.sh" ]

run.sh

echo Hello world!
echo -e "\033[1mHello World Bold\033[0m"
echo -e "\033[3mHello World Italics\033[0m"
echo -e "\033[4mHello World Underline\033[0m"
echo -e "\033[9mHello World Strikethrough\033[0m"
echo -e "\033[4;9mHello World Strikethrough Underline\033[0m"
echo -e "\033[31mHello World Red\033[0m"
echo -e "\033[1;31mHello World Bold Red\033[0m"
echo -e "\033[32mHello World Green\033[0m"
echo -e "\033[33mHello World Yellow\033[0m"
echo -e "\033[1;4;33mHello World Bold Yellow Underline\033[0m"
echo -e "\033[34mHello World Blue\033[0m"
echo -e "\033[35mHello World Magenta\033[0m"
echo -e "\033[36mHello World Cyan\033[0m"
echo -e "\033[1;3;36mHello World Bold Cyan Italics\033[0m"
echo -e "\033[37mHello World White\033[0m"
echo -e "\033[40;37mBlack Background\033[0m"
echo -e "\033[41mRed Background\033[0m"
echo -e "\033[42;37mGreen Background\033[0m"
echo -e "\033[43mYellow Background\033[0m"
echo -e "\033[44;37mBlue Background\033[0m"
echo -e "\033[45;37mMagenta Background\033[0m"
echo -e "\033[46mCyan Background\033[0m"
echo -e "\033[47mWhite Background\033[0m"