`entrypoint` declares the default entrypoint for the service container.
This overrides the `ENTRYPOINT` instruction from the service's Dockerfile.

If `entrypoint` is non-null, Compose ignores any default command from the image, for example the `CMD`
instruction in the Dockerfile.

See also [`command`](#command) to set or override the default command to be executed by the entrypoint process.

In its short form, the value can be defined as a string:
```yml
entrypoint: /code/entrypoint.sh
```

Alternatively, the value can also be a list, in a manner similar to the
[Dockerfile](https://docs.docker.com/reference/dockerfile/#cmd):

```yml
entrypoint:
  - php
  - -d
  - zend_extension=/usr/local/lib/php/extensions/no-debug-non-zts-20100525/xdebug.so
  - -d
  - memory_limit=-1
  - vendor/bin/phpunit
```

If the value is `null`, the default entrypoint from the image is used.

If the value is `[]` (empty list) or `''` (empty string), the default entrypoint declared by the image is ignored, or in other words, overridden to be empty.

### `env_file`

{{% include "compose/services-env-file.md" %}}

```yml
env_file: .env
```

Relative paths are resolved from the Compose file's parent folder. As absolute paths prevent the Compose
file from being portable, Compose warns you when such a path is used to set `env_file`.

Environment variables declared in the [`environment`](#environment) section override these values. This holds true even if those values are
empty or undefined.

`env_file` can also be a list. The files in the list are processed from the top down. For the same variable
specified in two environment files, the value from the last file in the list stands.

```yml
env_file:
  - ./a.env
  - ./b.env
```

List elements can also be declared as a mapping, which then lets you set additional
attributes.

#### `required`

{{< summary-bar feature_name="Compose required" >}}

The `required` attribute defaults to `true`. When `required` is set to `false` and the `.env` file is missing, Compose silently ignores the entry.

```yml
env_file:
  - path: ./default.env
    required: true # default
  - path: ./override.env
    required: false
```

#### `format`

{{< summary-bar feature_name="Compose format" >}}

The `format` attribute lets you use an alternative file format for the `env_file`. When not set, `env_file` is parsed according to the Compose rules outlined in [`Env_file` format](#env_file-format).

`raw` format lets you use an `env_file` with key=value items, but without any attempt from Compose to parse the value for interpolation. 
This let you pass values as-is, including quotes and `$` signs.

```yml
env_file:
  - path: ./default.env
    format: raw
```

#### `Env_file` format

Each line in an `.env` file must be in `VAR[=[VAL]]` format. The following syntax rules apply:

- Lines beginning with `#` are processed as comments and ignored.
- Blank lines are ignored.
- Unquoted and double-quoted (`"`) values have [Interpolation](interpolation.md) applied.
- Each line represents a key-value pair. Values can optionally be quoted.
  - `VAR=VAL` -> `VAL`
  - `VAR="VAL"` -> `VAL`
  - `VAR='VAL'` -> `VAL`
- Inline comments for unquoted values must be preceded with a space.
  - `VAR=VAL # comment` -> `VAL`
  - `VAR=VAL# not a comment` -> `VAL# not a comment`
- Inline comments for quoted values must follow the closing quote.
  - `VAR="VAL # not a comment"` -> `VAL # not a comment`
  - `VAR="VAL" # comment` -> `VAL`
- Single-quoted (`'`) values are used literally.
  - `VAR='$OTHER'` -> `$OTHER`
  - `VAR='${OTHER}'` -> `${OTHER}`
- Quotes can be escaped with `\`.
  - `VAR='Let\'s go!'` -> `Let's go!`
  - `VAR="{\"hello\": \"json\"}"` -> `{"hello": "json"}`
- Common shell escape sequences including `\n`, `\r`, `\t`, and `\\` are supported in double-quoted values.
  - `VAR="some\tvalue"` -> `some  value`
  - `VAR='some\tvalue'` -> `some\tvalue`
  - `VAR=some\tvalue` -> `some\tvalue`

`VAL` may be omitted, in such cases the variable value is an empty string.