Learning Perl

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How Do I Make a Perl Program?

A Whirlwind Tour of Perl

Scalar Data

Numbers

Strings

Perl's Built-in Warnings

Scalar Variables

Output with print

The if Control Structure

Getting User Input

The chomp Operator

The while Control Structure

The undef Value

The defined Function

Lists and Arrays

Accessing Elements of an Array

Special Array Indices

List Literals

List Assignment

Interpolating Arrays into Strings

The foreach Control Structure

Perl's Favorite Default: $_

Scalar and List Context

[left angle bracket]STDIN[right angle bracket] in List Context

Subroutines

System and User Functions

Defining a Subroutine

Invoking a Subroutine

Return Values

Arguments

Private Variables in Subroutines

The local Operator

Variable-length Parameter Lists

Notes on Lexical (my) Variables

The use strict Pragma

The return Operator

Hashes

What Is a Hash?

Hash Element Access

Hash Functions

Typical Use of a Hash

I/O Basics

Input from Standard Input

Input from the Diamond Operator

The Invocation Arguments

Output to Standard Output

Formatted Output with printf

Concepts of Regular Expressions

What Are Regular Expressions?

Using Simple Patterns

A Pattern Test Program

More About Regular Expressions

Character Classes

General Quantifiers

Anchors

Memory Parentheses

Precedence

Using Regular Expressions

Matches with m//

Option Modifiers

The Binding Operator, =~

Interpolating into Patterns

The Match Variables

Substitutions with s///

The split Operator

The join Function

More Control Structures

The unless Control Structure

The until Control Structure

Expression Modifiers

The Naked Block Control Structure

The elsif Clause

Autoincrement and Autodecrement

The for Control Structure

Loop Controls

Logical Operators

Filehandles and File Tests

What Is a Filehandle?

Opening a Filehandle

Fatal Errors with die

Using Filehandles

Reopening a Standard Filehandle

File Tests

Directory Operations

Moving Around the Directory Tree

Globbing

An Alternate Syntax for Globbing

Directory Handles

Recursive Directory Listing

Manipulating Files and Directories

Removing Files

Renaming Files

Links and Files

Making and Removing Directories

Modifying Permissions

Changing Ownership

Changing Timestamps

Using Simple Modules

Process Management

The system Function

The exec Function

The Environment Variables

Using Backquotes to Capture Output

Processes as Filehandles

Getting Down and Dirty with Fork

Sending and Receiving Signals

Strings and Sorting

Finding a Substring with index

Manipulating a Substring with substr

Formatting Data with sprintf

Advanced Sorting

Simple Databases

DBM Files and DBM Hashes

Manipulating Data with pack and unpack

Fixed-length Random-access Databases

Variable-length (Text) Databases

Some Advanced Perl Techniques

Trapping Errors with eval

Picking Items from a List with grep

Transforming Items from a List with map

Unquoted Hash Keys

More Powerful Regular Expressions

Slices

Beyond the Llama