The format of the env-file is explain at https://docs.docker.com/compose/env-file/.
# I'm using bash, but it applies with sh and zsh as well. $ echo $BASH_VERSION 4.4.23(1)-release # Create a simple env-file for testing. We're using = and ! to # push at some corner cases. $ echo 'THISISAVARIABLE=This is the value that even has an = sign!' > /tmp/concoction.env $ cat /tmp/concoction.env