Ruby Programming for Beginners
An Introduction to Learning Ruby Programming with Tutorials and Hands-On Examples
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The information contained in this book and its contents is not designed to replace or take the place of any form of medical or professional advice; and is not meant to replace the need for independent medical, financial, legal or other professional advice or services, as may be required. The content and information in this book has been provided for educational and entertainment purposes only.
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1. Introduction
Ruby is a cross-platform general purpose scripting language. Being a cross-platform language, it follows write once, run everywhere concept. When we say scripting language, in most cases, there is an interpreter which is responsible for executing the script. In this case, there is a Ruby interpreter which executes a Ruby script. Ruby supports multiple programming paradigms such as procedural, object-oriented and functional. This is a language that is easy to learn, read, understand and write. Hence it is often referred to as Programmers best friend.
1.1 History
A Japanese computer scientist called Yukihiro Matsumoto started working on designing the Ruby language in 1993 and the first stable version of Ruby appeared in 1995. According to Matsumoto, Ruby is influenced by Perl, Smalltalk, Eiffel, Ada, Basic, and Lisp. The first version of Ruby was 0.95 released in 1995 followed by several stable versions such as Ruby 1.0 in 1996, Ruby 1.2 in 1998, Ruby 1.4 in 1999, Ruby 1.6 in 2000 and so on. At the time of writing this book (March 2020), the latest version is Ruby 2.7.
1.2 Supported Platforms
Yukihiro Matsumoto first started developing Ruby on 4.3BSD , later moved to SunOS v4 and eventually to Linux . Today, Ruby supports most well-known platforms such as Linux, Windows, MAC OS, BSD (FreeBSD, DragonFly BSD, etc.), Solaris, AIX, Windows Phone, Windows CE, Symbian, etc . Ruby being a cross platform language, as long as there is no platform specific code in a program, a Ruby script written on one supported platform should work on another supported platform. For example, a script written on and for Linux should work on Windows without any problems.
Ruby interpreters are also available for ARM-Linux platforms. Which means running scripts on single board computers (SBC) such as Raspberry Pi, Beagleboard, Asus Tinkerboard S, Orange Pi, etc. is also possible. In the era of Cloud Computing, Ruby remains popular because of its power and ease of deployment on Virtual Machines (eg. AWS), Containers (eg. Docker), etc.
1.3 Ruby Implementations
The implementation language of Ruby is C. However, no C programming knowledge is required to learn Ruby. The de-facto reference implementation of Ruby by Yukihiro Matsumoto himself is called Matzs Ruby Interpreter, MRI or CRuby and is open-source. Alongside this, there are many more alternate implementations such as JRuby (Implemented in Java, runs inside JVM), IronRuby (Implemented in C#, runs inside .NET framework), Rubinius (Written in C++ and Ruby) and many more. In this book, we will stick to MRI.
2. Scope
A wide variety of things can be done using Ruby. This is the beauty of being a general purpose programming language. It is possible to build desktop applications, web applications, web services, etc. with Ruby. In fact, Ruby is a very powerful language on the web. There is a widely used web framework called Ruby on Rails which powers thousands of well-known websites such as GitHub, Airbnb, ASKfm, fiverr, Kickstarter, SlideShare, etc .
GUI applications for desktop can also be developed using Ruby with the help of appropriate bindings of GUI frameworks such as shoes, gtk2/3, etc . Most databases such as MySQL, MSSQL, SQLite, PostgreSQL, etc. are supported by Ruby.
Ruby projects can be easily extended using packages called as gems . The official package manager is known as RubyGems which hosts thousands of gems.
2.1 Prerequisites
Even if you have no programming background, you should have no problems in learning basic Ruby. However, you should be comfortable with using your computer and be well versed with using Shell/Terminal on Linux/MAC and Command Prompt/PowerShell on Windows. I am not saying that you should be a wizard of any sort but should know the basic commands, be comfortable with file system navigation using Shell, Terminal, Command Prompt or PowerShell. If you have any programming knowledge at all, you will really enjoy learning Ruby. If you have a choice to learn any other programming language before Ruby, I would suggest C or C++.
What will I learn from this Ruby book?
This book will teach you to write simple console applications in Ruby. When you come to the end of this book, you will be able to write Ruby scripts that interacts with the user, interacts with the file system, etc. Although Ruby is very useful on the web, this book does not contain any lessons on web specific development because the prerequisite of that is knowing basic web development using languages such as HTML, CSS, Javascript, etc. Having said that, if you are a web developer or know even the basics of web development using HTML, CSS, Javascript, etc., the basic knowledge of Ruby that you gain from this book should be enough for you to self-learn web development using Ruby.
3. Getting Started
You will need a PC/Laptop with Windows/Linux having a reasonably good hardware configuration or a MAC machine to write and execute Ruby scripts/programs. Ruby scripts can be written using any text editor including Notepad. I suggest Notepad++ (https://notepad-plus-plus.org/ ). Ruby scripts are plain-text files and carry the extension .rb .
Ruby is an interpreted language and a Ruby interpreter is needed to execute Ruby scripts. We will now see how to get started with Ruby interpreter on different platforms.
3.1 Installing Ruby on Windows
