# Predefined Variables

PHP provides predefined variables that represent external variables, built-in environment variables, and other information about the execution environment, such as the number and values of the arguments passed to the script in the CLI environment.

## Table of Contents

- Superglobals — Built-in variables that are always available in all scopes
- $GLOBALS — References all variables available in global scope
- $_SERVER — Server and execution environment information
- $_GET — Query string variables
- $_POST — Form data from HTTP POST requests
- $_FILES — HTTP File Upload variables
- $_REQUEST — HTTP Request variables
- $_SESSION — Session variables
- $_ENV — Environment variables
- $_COOKIE — HTTP Cookies
- $php_errormsg — The previous error message
- $http_response_header — HTTP response headers
- $argc — The number of arguments passed to script
- $argv — Array of arguments passed to script

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