> ## Documentation Index
> Fetch the complete documentation index at: https://notes.kodekloud.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Output Variables
> Terraform output variables store results from configuration files for later use, enhancing resource management and integration with other tools.
Terraform output variables are a powerful feature that allow you to store the results of expressions from your configuration files for later use. In previous lessons, we covered input variables and reference expressions; output variables complement these by enabling you to retrieve and present important output information after your infrastructure has been provisioned.
## Capturing Resource Attributes
Consider a configuration that creates a random pet name using Terraform's resource definitions. In this example, a resource called random\_pet generates a pet name, and an output variable called pet-name captures the generated id. This is especially useful for passing data to other tools or for quick resource verification.
Below is an example configuration:
```hcl theme={null}
resource "local_file" "pet" {
filename = var.filename
content = "My favorite pet is ${random_pet.my-pet.id}"
}
resource "random_pet" "my-pet" {
prefix = var.prefix
separator = var.separator
length = var.length
}
output "pet-name" {
value = random_pet.my-pet.id
desc = ""
}
```
The output block starts with the keyword `output` followed by the variable name. Inside the block, the **value** argument is required and uses a reference expression (`random_pet.my-pet.id`). Although the **desc** argument is optional, it is a good practice to include a brief description of the output's purpose.
Use meaningful descriptions for your output variables. This practice enhances code readability and aids in documentation, especially when collaborating with other team members.
## Configuration of Related Variables
To support the resources defined above, ensure the following variables are declared in your configuration:
```hcl theme={null}
variable "filename" {
default = "/root/pets.txt"
}
variable "content" {
default = "I love pets!"
}
variable "prefix" {
default = "Mrs"
}
variable "separator" {
default = "."
}
variable "length" {
default = "1"
}
```
These variable definitions set the necessary defaults and ensure the configuration runs smoothly during execution.
## Displaying Outputs with Terraform
When you run `terraform apply`, Terraform automatically displays the output variables after resource creation. For example:
```bash theme={null}
$ terraform apply
...
Outputs:
pet-name = Mrs.gibbon
```
You can also retrieve the value of output variables at any time using the `terraform output` command. Running the command without any arguments lists all outputs:
```bash theme={null}
$ terraform output
pet-name = Mrs.gibbon
```
To display an individual output variable, simply specify its name:
```bash theme={null}
$ terraform output pet-name
Mrs.gibbon
```
Output variables are invaluable for quickly viewing details about your provisioned resources and for integrating with other infrastructure as code tools, ad hoc scripts, or configuration management systems like Ansible.
## Further Reading
For more comprehensive information on Terraform output variables and other configuration concepts, please refer to the following resources:
* [Terraform Official Documentation](https://www.terraform.io/docs)
* [Terraform CLI Documentation](https://www.terraform.io/cli)
By incorporating output variables into your Terraform configurations, you can streamline the process of accessing essential resource details and improve the overall management of your infrastructure.