Terraform Command Cheatsheet

A comprehensive reference for Terraform infrastructure as code.

Basic Commands

Initialize

terraform init                       # Initialize directory
terraform init -upgrade              # Upgrade providers
terraform init -reconfigure          # Reconfigure backend

Plan

terraform plan                       # Show execution plan
terraform plan -out=plan.tfplan      # Save plan
terraform plan -destroy              # Plan destroy
terraform plan -target=resource      # Target specific resource

Apply

terraform apply                      # Apply changes
terraform apply plan.tfplan          # Apply saved plan
terraform apply -auto-approve        # Skip confirmation
terraform apply -target=resource     # Apply specific resource

Destroy

terraform destroy                    # Destroy infrastructure
terraform destroy -auto-approve      # Skip confirmation
terraform destroy -target=resource   # Destroy specific resource

Other Commands

terraform validate                   # Validate configuration
terraform fmt                        # Format code
terraform show                       # Show current state
terraform output                     # Show outputs
terraform refresh                    # Refresh state
terraform graph                      # Generate dependency graph

State Management

State Commands

terraform state list                 # List resources
terraform state show resource        # Show resource
terraform state mv source dest       # Move resource
terraform state rm resource          # Remove from state
terraform state pull                 # Pull remote state
terraform state push                 # Push state

Workspace

terraform workspace list             # List workspaces
terraform workspace new dev          # Create workspace
terraform workspace select dev       # Switch workspace
terraform workspace delete dev       # Delete workspace

Configuration Syntax

Provider

terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 4.0"
    }
  }
}

provider "aws" {
  region = "us-east-1"
}

Resource

resource "aws_instance" "web" {
  ami           = "ami-0c55b159cbfafe1f0"
  instance_type = "t2.micro"
  
  tags = {
    Name = "WebServer"
  }
}

Variables

variable "instance_type" {
  description = "EC2 instance type"
  type        = string
  default     = "t2.micro"
}

variable "availability_zones" {
  type    = list(string)
  default = ["us-east-1a", "us-east-1b"]
}

Outputs

output "instance_ip" {
  value       = aws_instance.web.public_ip
  description = "Public IP of instance"
}

Data Sources

data "aws_ami" "ubuntu" {
  most_recent = true
  owners      = ["099720109477"]
  
  filter {
    name   = "name"
    values = ["ubuntu/images/hvm-ssd/ubuntu-focal-20.04-amd64-server-*"]
  }
}

Locals

locals {
  common_tags = {
    Environment = "production"
    ManagedBy   = "Terraform"
  }
}

Modules

Use Module

module "vpc" {
  source = "./modules/vpc"
  
  cidr_block = "10.0.0.0/16"
  name       = "main-vpc"
}

Module Output

output "vpc_id" {
  value = module.vpc.vpc_id
}

Backend Configuration

S3 Backend

terraform {
  backend "s3" {
    bucket = "my-terraform-state"
    key    = "prod/terraform.tfstate"
    region = "us-east-1"
  }
}

Common Patterns

Count

resource "aws_instance" "server" {
  count         = 3
  ami           = "ami-0c55b159cbfafe1f0"
  instance_type = "t2.micro"
  
  tags = {
    Name = "Server-${count.index}"
  }
}

For_each

resource "aws_instance" "server" {
  for_each = toset(["web", "app", "db"])
  
  ami           = "ami-0c55b159cbfafe1f0"
  instance_type = "t2.micro"
  
  tags = {
    Name = each.key
  }
}

Conditional

resource "aws_instance" "server" {
  count = var.create_instance ? 1 : 0
  
  ami           = "ami-0c55b159cbfafe1f0"
  instance_type = "t2.micro"
}

Dynamic Blocks

resource "aws_security_group" "example" {
  name = "example"
  
  dynamic "ingress" {
    for_each = var.ingress_rules
    content {
      from_port   = ingress.value.from_port
      to_port     = ingress.value.to_port
      protocol    = ingress.value.protocol
      cidr_blocks = ingress.value.cidr_blocks
    }
  }
}

Functions

Common Functions

# String functions
upper("hello")
lower("HELLO")
title("hello world")
format("Hello, %s", var.name)

# Numeric functions
min(1, 2, 3)
max(1, 2, 3)
ceil(5.1)
floor(5.9)

# Collection functions
length(var.list)
concat(list1, list2)
merge(map1, map2)
lookup(map, "key", "default")

# Type conversion
tostring(123)
tonumber("123")
tolist(set)
toset(list)

Import Existing Resources

Import

terraform import aws_instance.web i-1234567890abcdef0

Quick Reference

Command	Description
terraform init	Initialize
terraform plan	Show plan
terraform apply	Apply changes
terraform destroy	Destroy all
terraform validate	Validate config
terraform fmt	Format code
terraform state list	List resources
terraform output	Show outputs

Best Practices

1. Use version control
2. Use remote state (S3, Terraform Cloud)
3. Use modules for reusability
4. Use variables for flexibility
5. Use workspaces for environments
6. Run terraform fmt regularly
7. Use terraform validate before apply
8. Use -target sparingly
9. Document your code
10. Use consistent naming

Resources

• Official Documentation: https://www.terraform.io/docs/
• Terraform Registry: https://registry.terraform.io/
• Best Practices: https://www.terraform-best-practices.com/
• Learn Terraform: https://learn.hashicorp.com/terraform