CommonJS modules are primarily used in Node.js for server-side JavaScript development.

In CommonJS, you export modules using `module.exports` or `exports`, e.g., `module.exports = { functionName: function() { … } }`.

ES6 modules use `import` and `export` statements, while CommonJS uses `require()` and `module.exports`.

You can use named imports in ES6, e.g., `import { specificFunction } from './module.js'`.

The `_<sub>init</sub>_<sub>.py</sub>` file marks a directory as a Python package and can be used to execute package initialization code.

You can use the `from` keyword, e.g., `from module<sub>name</sub> import specific<sub>function</sub>`.

The module system was introduced in Java 9.

The `module-info.java` file defines a module's dependencies, exported packages, and services.

C++20 introduced modules to the C++ language.

C++ modules offer faster compilation times, better encapsulation, and reduced header dependencies.

Ruby modules are used for namespacing and mixins, allowing code to be shared across multiple classes.

You use the `include` keyword followed by the module name, e.g., `include ModuleName`.

The command `go mod init` initializes a new module in Go.

The `go.mod` file is created to manage dependencies in Go modules.

You declare a module in Rust using the `mod` keyword, e.g., `mod module<sub>name</sub>;`.

The `use` keyword in Rust is used to bring items from modules into scope, similar to `import` in other languages.

The default access level for entities in Swift modules is `internal`.

You add the `public` keyword before the class or function declaration, e.g., `public class ClassName { … }`.

Autoloading in PHP automatically includes class files when they are used, eliminating the need for multiple `include` or `require` statements.

PSR-4 defines the autoloading specifications in PHP.

TypeScript modules are very similar to ES6 modules but add support for type information and additional features like `namespace`.

The `export` keyword in TypeScript is used to make a declaration available for use in other modules.

You import a Haskell module using the `import` keyword, e.g., `import ModuleName`.

The `qualified` keyword is used to import a module with a namespace, preventing name clashes, e.g., `import qualified Data.Map as Map`.

In Scala, packages serve a similar purpose to Java packages, organizing code into namespaces.

You create a singleton object in Scala using the `object` keyword instead of `class`, e.g., `object SingletonName { … }`.