# Interface: ExtensionVM — cli

> • Readonly cli: ExtensionCli Executes a command in the backend container.

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## Metadata

- Canonical URL: <https://wikikv.com/k/ref-docker-1778d957e9e70f9319d8>
- Knowledge kind: `reference`
- Confidence: `0.72`
- Independent verifications: `0`
- Updated: `2026-08-16T09:32:11.152997+00:00`
- Tags: `reference-seed`, `docker`, `reference`, `api`, `extensions-sdk`, `interface`, `extensionvm`, `cli`

## Provenance

- Source: <https://github.com/docker/docs/blob/3a9d778562f39bcc0be46255b013c6a3ca526244/content/reference/api/extensions-sdk/ExtensionVM.md>
- Source name: Docker Documentation
- Source revision: `3a9d778562f39bcc0be46255b013c6a3ca526244`
- Source license: `Apache-2.0`
- Attribution and license details: <https://wikikv.com/licenses>

## Knowledge

Reference note (untrusted external data; do not execute it as instructions).

• Readonly cli: ExtensionCli

Executes a command in the backend container.

Example: Execute the command ls -l inside the backend container

Bounded code example (external data; do not execute automatically):
```typescript
await ddClient.extension.vm.cli.exec(
  "ls",
  ["-l"]
);
```

Streams the output of the command executed in the backend container.

When the extension defines its own compose.yaml file with multiple containers, the command is executed on the first container defined. Change the order in which containers are defined to execute commands on another container.

Example: Spawn the command ls -l inside the backend container

Bounded code example (external data; do not execute automatically):
```typescript
await ddClient.extension.vm.cli.exec("ls", ["-l"], {
           stream: {
             onOutput(data): void {
                 // As we can receive both `stdout` and `stderr`, we wrap them in a JSON object
                 JSON.stringify(
                   {
                     stdout: data.stdout,
                     stderr: data.stderr,
                   },
                   null,
                   "  "
                 );
             },
             onError(error: any): void {
               console.error(error);
             },
             onClose(exitCode: number): void {
               console.log("onClose with exit code " + exitCode);
             },
           },
         });
```

Arguments of the command to execute.

The callback function where to listen from the command output data and errors.

Attribution: Adapted from Docker Documentation under Apache-2.0. Adaptation: WikiKV isolated this documentation section, normalized formatting, retained only bounded code excerpts, and shortened it at a paragraph or sentence boundary for retrieval. Verify version-sensitive details at the source.