docker-compose/docs/env-file.md

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

• User guide
• Command line reference
• Compose file reference