> ## Documentation Index
> Fetch the complete documentation index at: https://errand.nuvrel.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# env

> Read an environment variable.

`env(name)` reads the environment variable `name` and returns its value. An optional second argument provides a fallback when the variable is not set.

## Signature

```
env(name string) string
env(name string, default string) string
```

## Example

Configure the deployment target from the CI environment, with a safe fallback for local development:

```hcl theme={null}
computed "registry" {
  description = "Container registry from the CI environment"
  expression  = env("CI_REGISTRY", "localhost:5000")
}

computed "registry_user" {
  description = "Registry username from the CI environment"
  expression  = env("CI_REGISTRY_USER", "developer")
}

task "push" {
  description = "Push the image to the registry"
  commands = [
    "docker push ${computed.registry}/${var.app}:${var.tag}",
  ]
}
```

On CI, `CI_REGISTRY` is set to the real registry. Locally, images are pushed to `localhost:5000`.

## Notes

* When called with one argument and the variable is not set, `env` returns an empty string `""`.
* Use a default to avoid empty strings in commands or expressions that require a value.
* `env` reads the process environment at evaluation time. Changes to the environment after the playbook starts are not visible.