Bash is a very common *nix shell, and it's programming language is purely procedural and focused on command execution. Object Oriented Programming (OOP) is a programming paradigm that represents the elements of a problem as entities with a set of properties and actions that it can execute. If you use Bash to write very simple and short scripts, procedural programming is just fine, you don't need more. But if your program becomes more and more bigger, a monster program (> 1000 lines), then you need a better way to structure your program to make it easy to maintain and read. Of course, Bash lacks OOP features, but with some tricks you can simulate it with a few lines added, and I'll show you how.