Terraform Core Commands

Four commands form the backbone of every Terraform workflow. You use them in almost every project, every day. This topic explains what each command does, when to run it, and what output to expect.

The Terraform Workflow at a Glance

Write .tf files
      |
      v
terraform init      ← Download providers and set up the project
      |
      v
terraform plan      ← Preview changes before touching anything
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      v
terraform apply     ← Create or update real infrastructure
      |
      v
terraform destroy   ← Remove all resources when no longer needed

Think of these four commands as: Set up → Preview → Build → Clean up.

terraform init

The first thing you always run in a new Terraform project is terraform init. This command prepares your working directory.

What init Does

  • Reads your .tf files to find out which providers you declared
  • Downloads those provider plugins from the Terraform Registry
  • Creates a hidden .terraform folder to store downloaded plugins
  • Creates a .terraform.lock.hcl file that records the exact plugin versions used

When to Run init

  • When starting a new project
  • When you add a new provider to your configuration
  • When a teammate has updated the provider versions
terraform init

Sample Output

Initializing the backend...
Initializing provider plugins...
- Finding hashicorp/aws versions matching "~> 5.0"...
- Installing hashicorp/aws v5.31.0...
Terraform has been successfully initialized!

terraform plan

Before making any real changes, terraform plan shows you exactly what Terraform intends to do. No changes happen at this stage — it is purely a preview.

What plan Does

  1. Reads your current .tf files
  2. Reads the current state of your infrastructure (from the state file)
  3. Compares the two and calculates the difference
  4. Prints a list of actions: what will be created, changed, or deleted

Reading the Plan Output

+ resource will be CREATED
~ resource will be UPDATED in place
- resource will be DESTROYED
-/+ resource will be DESTROYED and re-created

A + means something new appears. A - means something disappears. A ~ means something changes but stays.

terraform plan

Saving a Plan to a File

terraform plan -out=myplan.tfplan

Saving the plan is important in CI/CD pipelines. You generate the plan, a human reviews it, and then you apply that exact saved plan — ensuring no surprises.

terraform apply

Once you review the plan and confirm it looks correct, terraform apply executes the changes against real infrastructure.

terraform apply

Terraform shows the plan again and asks:

Do you want to perform these actions?
  Terraform will perform the actions described above.
  Only 'yes' will be accepted to approve.

  Enter a value: yes

Type yes and press Enter. Terraform contacts the cloud provider APIs and creates or modifies your resources.

Skipping the Prompt (Automation)

terraform apply -auto-approve

Use this flag in automated pipelines where no human is present to type yes. Never use it blindly — always know what the plan contains before automating approval.

Applying a Saved Plan

terraform apply myplan.tfplan

When you apply a saved plan file, Terraform skips the prompt entirely and applies exactly what was planned.

terraform destroy

When you no longer need the infrastructure, terraform destroy removes everything Terraform created.

terraform destroy

This is invaluable for learning environments and temporary test setups. You spin up infrastructure, test it, then destroy it — paying only for the time it ran.

Destroying a Specific Resource

terraform destroy -target=aws_instance.web_server

The -target flag limits the destroy operation to one specific resource rather than the entire configuration.

Other Useful Commands

CommandWhat It Does
terraform validateChecks your configuration for syntax errors without contacting any provider
terraform fmtAutomatically formats your .tf files to follow standard style
terraform showDisplays the current state or a saved plan in human-readable format
terraform outputPrints the current output values from your state

Key Points

  • terraform init sets up the project and downloads provider plugins — always the first step.
  • terraform plan previews changes safely — nothing is created or destroyed at this stage.
  • terraform apply executes the plan and creates real infrastructure.
  • terraform destroy removes all managed resources — essential for cleanup.
  • Always run terraform fmt and terraform validate before committing code to version control.
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