How to set PS1 in Docker Container

Question

I want to set $PS1 environment variable to the container. It helps me to identify multilevel or complex docker environment setup. Currently docker container prompts with:

root@container-id# 

If I can change it as following , I can identify the container by looking at the $PS1 prompt itself.

[Level-1]root@container-id# 

I did experiments by exporting $PS1 by making my own image (Dockerfile), .profile file etc. But it's not reflecting.

Answer 1

This Dockerfile sets PS1 by doing:

RUN echo 'export PS1="[\u@docker] \W # "' >> /root/.bash_profile

Answer 2

I had the same problem but in docker-compose context.
Here is how I managed to make it work:

# docker-compose.yml

version: '3'
services:
  my_service:
    image: my/image
    environment:
      - "PS1=$$(whoami):$$(pwd) $$ "

Just pass PS1 value as an environment variable in docker-compose.yml configuration file.
Notice how dollars signs need to be escaped to prevent docker-compose from interpolating values (documentation).