> For the complete documentation index, see [llms.txt](https://docs.takomo.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.takomo.io/parameter-resolvers/built-in-parameter-resolvers/command-resolver.md).

# Command resolver

The command resolver executes a specified shell command and uses the command output as a parameter value.

### Properties

Here are the properties of the command resolver:

| Key                    | Required | Type    | Description                                                                                                                                                                              |
| ---------------------- | -------- | ------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| resolver               | yes      | string  | Resolver name, this must be **cmd**.                                                                                                                                                     |
| command                | yes      | string  | Shell command to execute.                                                                                                                                                                |
| confidential           | no       | boolean | Conceal the resolved parameter value from logs, defaults to **false**                                                                                                                    |
| immutable              | no       | boolean | Mark the parameter as immutable, defaults to **false**                                                                                                                                   |
| exposeStackCredentials | no       | boolean | Make the current stack's AWS credentials available for the shell command. Defaults to false. Added in Takomo v3.11.0.                                                                    |
| exposeStackRegion      | no       | boolean | Make the current stack's region available for the shell command. Defaults to false. Added in Takomo v3.11.0.                                                                             |
| capture                | no       | string  | Controls how to capture the output of the executed shell command. By default, all output is captured. To capture only the last line, set this to **last-line.** Added in Takomo v3.11.0. |

### Environment variables available in the shell command

The following environment variables are available in the shell command:

| Name                     | Description                                                                                                        |
| ------------------------ | ------------------------------------------------------------------------------------------------------------------ |
| AWS\_ACCESS\_KEY\_ID     | If `exposeStackCredentials` is **true**, this will hold the access key id of credentials of the current stack.     |
| AWS\_SECRET\_ACCESS\_KEY | If `exposeStackCredentials` is **true**, this will hold the secret access key of credentials of the current stack. |
| AWS\_SESSION\_TOKEN      | If `exposeStackCredentials` is **true**, this will hold the session token of credentials of the current stack.     |
| AWS\_SECURITY\_TOKEN     | If `exposeStackCredentials` is **true**, this will hold the session token of credentials of the current stack.     |
| AWS\_DEFAULT\_REGION     | IF `exposeStackRegion` is **true**, this will hold the region of the current stack.                                |

### Example

Use contents of the **/home/password.txt** file as parameter value:

```yaml
parameters:
  Password:
    resolver: cmd
    command: cat /home/password.txt
```

##


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.takomo.io/parameter-resolvers/built-in-parameter-resolvers/command-resolver.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.