Subjects

JAVASCRIPT HTML CSS PYTHON SQL JAVA CPP CSHARP PHP TYPESCRIPT C RUBY GO SWIFT KOTLIN RUST R BASH SCALA OBJECTIVE-C DART PERL LUA MATLAB XML JSON MARKDOWN ASSEMBLY LATEX YAML SOLIDITY BLOCKCHAIN

Topics

Perl Basics

Introduction to Perl Installing Perl Perl Syntax Perl Variables Perl Data Types Perl Operators Perl Comments Perl Print Statements Perl Input/Output Perl Command Line Arguments

Control Structures

Perl If-Else Statements Perl Unless Statement Perl Switch Statement Perl For Loops Perl While Loops Perl Do-While Loops Perl Loop Control Statements Perl Ternary Operator

Perl Subroutines

Defining Perl Subroutines Perl Subroutine Arguments Perl Return Values Perl Anonymous Subroutines Perl Recursive Subroutines Perl Subroutine References

Perl Data Structures

Perl Arrays Perl Hashes Perl Multidimensional Arrays Perl Array and Hash Slices Perl References Perl Complex Data Structures

Perl String Manipulation

Perl String Basics Perl String Functions Perl Regular Expressions Perl Pattern Matching Perl String Formatting Perl Here Documents

Perl File Handling

Perl File Open and Close Perl File Reading Perl File Writing Perl File Appending Perl Directory Handling Perl File Test Operators

Perl Modules

Using Perl Modules Creating Perl Modules Perl Standard Modules Perl CPAN Perl Module Versioning Perl Object-Oriented Modules

Perl Object-Oriented Programming

Perl OOP Basics Perl Classes and Objects Perl Inheritance Perl Encapsulation Perl Polymorphism Perl Method Overriding

Perl Exception Handling

Perl Die and Warn Perl Eval Function Perl Try-Catch Blocks Perl Custom Exceptions Perl Error Handling Best Practices

Perl Database Interaction

Perl DBI Module Perl Database Connection Perl SQL Queries Perl Prepared Statements Perl Database Transactions

Perl Web Development

Perl CGI Programming Perl and HTML Forms Perl Session Handling Perl Cookies Perl Web Frameworks (e.g., Mojolicious)

Perl Network Programming

Perl Socket Programming Perl Client-Server Communication Perl and HTTP Perl and FTP Perl and Email Handling

Perl System Administration

Perl Process Management Perl File System Operations Perl System Information Retrieval Perl and Shell Commands Perl Log File Analysis

Perl Testing and Debugging

Perl Debugging Techniques Perl Unit Testing Perl Test::More Module Perl Code Coverage Perl Profiling

Advanced Perl Concepts

Perl References and Pointers Perl Typeglobs Perl Symbol Tables Perl Tie Interface Perl Closures Perl Benchmarking Perl Internals

Perl Command-Line Arguments

Command-line arguments are a powerful feature in Perl that allow users to pass information to a script when it's executed. These arguments can significantly enhance the flexibility and functionality of your Perl programs.

Accessing Command-Line Arguments

In Perl, command-line arguments are stored in the special array @ARGV. Each element of this array represents a separate argument passed to the script.


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

print "Number of arguments: " . scalar(@ARGV) . "\n";
print "Arguments: @ARGV\n";

When you run this script with arguments, it will display the number of arguments and list them all.

Processing Arguments

You can easily iterate through the arguments using a Perl for loop or access them directly by index:


foreach my $arg (@ARGV) {
    print "Argument: $arg\n";
}

print "First argument: $ARGV[0]\n" if @ARGV > 0;

Shift Command

The shift function is commonly used to process arguments one by one:


while (my $arg = shift @ARGV) {
    print "Processing: $arg\n";
}

Getopt::Long Module

For more complex argument handling, Perl provides the Getopt::Long module. This module allows you to define and parse command-line options easily:


use Getopt::Long;

my $verbose = 0;
my $name = '';

GetOptions(
    'verbose' => \$verbose,
    'name=s'  => \$name
);

print "Verbose mode on\n" if $verbose;
print "Name: $name\n" if $name;

Best Practices

Always validate and sanitize command-line inputs to prevent security vulnerabilities.
Provide clear usage instructions for your script, especially when expecting specific arguments.
Use Getopt::Long for scripts with multiple or complex options.
Consider using die and warn for handling invalid arguments.

Conclusion

Command-line arguments in Perl offer a flexible way to make your scripts more dynamic and user-friendly. By mastering these techniques, you can create more versatile and powerful Perl applications. Remember to combine this knowledge with other Perl concepts like input/output operations and error handling for robust script development.