Docker: Executing Startup Script When Running Container Interactively

PROBLEM

When running the Docker container interactively (ex: docker run –rm -it myimage), you want to run a startup script every time.

SOLUTION

For Ubuntu, Debian and Centos images, write the startup script to /root/.bashrc:

# UBUNTU
FROM ubuntu:latest
RUN echo "echo 'Welcome!'" >> /root/.bashrc
WORKDIR /home

# DEBIAN
FROM debian:latest
RUN echo "echo 'Welcome!'" >> /root/.bashrc
WORKDIR /home

# CENTOS
FROM centos:latest
RUN echo "echo 'Welcome!'" >> /root/.bashrc
WORKDIR /home

For Alpine image, it’s a little different because it uses Ash shell. Besides writing the startup script to /root/.profile, you also need to set that path to an environment variable called ENV:

FROM alpine:latest
ENV ENV=/root/.profile
RUN echo "echo 'Welcome!'" > $ENV
WORKDIR /home