What is HCL (HashiCorp Configuration Language)?

HCL (HashiCorp Configuration Language) is the configuration language used by Terraform (and other HashiCorp tools). It is designed to be both human-readable and machine-parseable. Key syntax elements: Blocks: define resources, providers, variables, outputs. resource "aws_instance" "web" { ami = "ami-123" instance_type = "t3.micro" }. Arguments: key-value pairs within blocks. Expressions: reference values: var.region, aws_vpc.main.id. Comments: # or // for single-line, /* */ for multi-line. String interpolation: "${var.prefix}-server". HCL supports conditionals (condition ? true_val : false_val), for expressions, count and for_each meta-arguments for resource iteration. Files use the .tf extension.