Environment file

Compose supports declaring default environment variables in an environment file named .env placed in the folder docker-compose command is executed from (current working directory).

Compose expects each line in an env file to be in VAR=VAL format. Lines beginning with # (i.e. comments) are ignored, as are blank lines.

Note: Values present in the environment at runtime will always override those defined inside the .env file. Similarly, values passed via command-line arguments take precedence as well.

Those environment variables will be used for variable substitution in your Compose file, but can also be used to define the following CLI variables:

  • COMPOSE_API_VERSION
  • COMPOSE_FILE
  • COMPOSE_HTTP_TIMEOUT
  • COMPOSE_PROJECT_NAME
  • DOCKER_CERT_PATH
  • DOCKER_HOST
  • DOCKER_TLS_VERIFY

More Compose documentation