Perl Tutorial

• Introduction to Perl
• Installation and Environment Setup
• Syntax of a Perl Program
• Hello World Program in Perl
• Perl vs C/C++
• Perl vs Java
• Perl vs Python

Fundamentals

• Modes of Writing a Perl Code
• Boolean Values
• Operators
• Variables
• Variables and its Types
• Scope of Variables
• Modules in Perl
• Packages in Perl
• Number and its Types
• Directories with CRUD operations

Input and Output

• Use of print() and say() in Perl
• Perl | print operator
• Use of STDIN for Input

Control Flow

• Decision Making
• Loops
• Perl given-when Statement
• Perl goto operator
• next operator
• redo operator
• last in loop

Arrays and Lists

• Arrays
• Array Slices
• Getting the Number of Elements of an Array
• Reverse an array
• Sorting of Arrays
• Useful Array functions
• Arrays (push, pop, shift, unshift)
• Implementing a Stack
• List and its Types
• List Functions

Hash

• Introduction to Hash
• Working of a Hash
• Hash Operations
• Sorting a Hash
• Multidimensional Hashes
• Hash in Scalar and List Context
• Useful Hash functions

Scalars

• Scalars
• Comparing Scalars
• scalar keyword

Strings

• Quoted, Interpolated and Escaped Strings
• Multi-line Strings | Here Document
• Sorting mixed Strings in Perl
• String Operators
• Useful String Operators
• String functions (length, lc, uc, index, rindex)
• Useful String functions
• Automatic String to Number Conversion or Casting
• Count the frequency of words in text
• Removing leading and trailing white spaces (trim)

Object Oriented Programming in Perl

• Introduction to OOPs
• Classes
• Objects
• Methods
• Constructors and Destructors
• Method Overriding
• Inheritance
• Polymorphism
• Encapsulation

Subroutines

• Subroutines or Functions
• Function Signature in Perl
• Passing Complex Parameters to a Subroutine
• Mutable and Immutable parameters
• Multiple Subroutines
• Use of return() Function
• References
• Pass By Reference
• Recursion in Perl

Regular Expressions

• Regular Expressions
• Operators in Regular Expression
• Regex Character Classes
• Special Character Classes in Regular Expressions
• Quantifiers in Regular Expression
• Backtracking in Regular Expression
• ‘e’ modifier in Regex
• ‘ee’ Modifier in Regex
• pos() function in Regex
• Regex Cheat Sheet
• Searching in a File using regex

File Handling

• File Handling Introduction
• Opening and Reading a File
• Writing to a File
• Appending to a File
• Reading a CSV File
• File Test Operators
• File Locking
• Use of Slurp Module
• Useful File-handling functions

Context Sensitivity

• Scalar Context Sensitivity
• List Context Sensitivity
• STDIN in Scalar and List Context

CGI Programming

• CGI Programming
• File Upload in CGI
• GET vs POST in CGI

Misc

• Breakpoints of a Debugger
• Exiting from a Script
• Creating Excel Files
• Reading Excel Files
• Number Guessing Game using Perl
• Database management using DBI
• Accessing a Directory using File Globbing
• Use of Hash bang or Shebang line
• Useful Math functions

Hello World Program in Perl

A simple "Hello World" program in Perl looks like this:

#!/usr/bin/perl
use strict;
use warnings;

print "Hello, World!\n";

Here's a brief breakdown of what each line does:

1. #!/usr/bin/perl: This is called a shebang line. It tells the operating system to execute the script with Perl. This is primarily useful if you're running the script from a Unix-like environment.

2. use strict;: This is a pragma to enforce strict variable declaration, which can help catch some common programming errors.

3. use warnings;: This enables warnings to catch potential issues in your script.

4. print "Hello, World!\n";: This line prints the string "Hello, World!" to the console, followed by a newline character (\n).

To execute the program:

1. Save the code in a file, say hello.pl.
2. Provide execute permission (in Unix-like systems) with: chmod +x hello.pl
3. Run the program with: ./hello.pl

Alternatively, you can run it using the Perl interpreter directly, without needing the shebang line or execute permissions:

perl hello.pl