Perl

1. Perl Introduction

   Scalars, arrays, hashes, control flow, and subroutines in brief.

2. Data Types

   Scalar, array, and hash data and context.

3. Syntax

   Statements, loops, and compound statements.

4. Operators

   Operators, precedence, and quote-like constructs.

5. Subroutines

   Defining subs, arguments, scoping, and prototypes.

6. References and Data Structures

   References and nested data structures.

7. Regular Expressions

   Pattern syntax, modifiers, and matching.

8. Objects and OO Programming

   Packages, bless, method resolution, and inheritance.

9. Modules

   Packages, symbol tables, and module loading.

10. Security

    Taint mode and safe handling of untrusted data.

11. Interprocess Communication

    Signals, pipes, sockets, and process management.

12. Built-in Functions

    Reference of built-in functions.

Each section links to the official page. Titles and summaries by Extra Credit; the docs belong to their authors.

Source: endoflife.date