Docker: ENTRYPOINT vs CMD
FROM ubuntu:23.04
RUN apt-get update
RUN apt-get install -y curl
ENTRYPOINT ["curl"] # fixed part
CMD ["--silent", "https://httpbin.org/get"] # replacable part
By default if you run a container based on this image, Docker will execute a command which is a combination of the ENTRYPOING + CMD.
However, on the command-line where you call docker run, you can provide a replacement for the CMD part.
- Build the image:
$ docker build -t mydocker .
- Running container this way will execute
curl --silent https://httpbin.org/get
$ docker run --rm mydocker
- The user can replace the CMD part, so if we run this command, docker will execude
curl https://szabgab.com/
$ docker run --rm mydocker https://szabgab.com/