# Ruby > Published Jan 01 0001, last updated Nov 11 2020 > By Ryan Fleck and written without LLMs! > Original manual at > Incredible writing of astonishing quality and insight - Happy Hacking! # Hello Ruby ```ruby puts "Hello, Ruby!" ``` # What is Ruby? In descriptors: high-level, object-oriented and interpreted. Ruby occupies a similar market space to _Python_, with both striving to create a more human-readable language. I'll update this as I learn more, with my primary resources being [Ruby Koans](http://rubykoans.com/) and [Codecademy](https://www.codecademy.com/courses/learn-ruby). In code blocks below, `#>` indicates text that is printed to the console. # Why use Ruby? I'm not, really; it seems like a fun language with lots of respected devs. I don't have time to learn or tinker with this very flexible scripting lang at the moment. At one point in early 2019, I spent a short, intense period binge-learning C++, then Ruby, in order to meet requirements and complete technical interviews at C++/Ruby shops. # The Basics Running `ruby -v` will print your ruby version. If you have a 'good' OS, you should have a version built in. Upgrade if the version is less than 2. `ruby` runs ruby programs. `irb` starts an interactive ruby prompt. On Debian, it is best to add `/.gem/ruby/2.3.0/bin` to your PATH in `~/.profile`, and `gem: --user-install` to your `~/.gemrc`. Be careful not to run gem, bundle, etc as root. Adding this user bin to your PATH makes it easy to use tools like [RuboCop](https://rubocop.readthedocs.io/en/latest/) (`gem install rubocop`) to `rubocop --fix-layout *.rb` your ruby files. **Resources:** 1. Ruby: [Why's Poignant Guide](https://poignant.guide/book/) 1. Rails: [Rails Guides](https://guides.rubyonrails.org/) and [railstutorial.org](https://www.railstutorial.org/book/beginning) are good. 1. [Ruby Koans](http://rubykoans.com/) 1. [The Odin Project](https://www.theodinproject.com/courses) 1. [Writing CLI progs in Ruby](https://www.honeybadger.io/blog/writing-command-line-apps-in-ruby/) ## Data Types ```ruby number = 18 boolean = true string = "Hello" ``` ## Console Output ```ruby puts "String" #Appends a newline print "String" ``` `puts` and `print` are used for output, the only difference being that `puts` appends a newline after printing the given string. ## Arithmetic ```ruby x = (3 + 3) / 2 #Brackets x = 3 ** 2 #Exponents x = 3 / 3 #Division x = 3 * 3 #Multiplication x = 3 + 3 #Addition x = 3 - 3 #Subtraction x = 3 % 3 #Modulo ``` The only operation that may be foreign is _modulo_, which is the _remainder of a division_. For instance, running `128 / 13` will give 9, and `128 % 13` will give 11. Stepping backwards, `13 * 9` is 117, and adding 11 gives 128. ## Using Methods ```ruby x = "String length".length puts x #> 13 ``` Methods without arguments (or to be invoked with only default arguments,) can be called without brackets `( )`. ```ruby puts "RoFlMaO".upcase.reverse.downcase #> oamlfor ``` ## String Manipulation **Reverse** ```ruby x = "Ruby is interesting...".reverse puts x #> ...gnitseretni si ybuR ``` **Upcase/Downcase** ```ruby puts "Ruby is interesting...".upcase #> RUBY IS INTERESTING... puts "Ruby is interesting...".downcase #> ruby is interesting... ``` ## Basic Syntax Comments can be included anywhere, and are formatted as follows: ```ruby # Single line. =begin Multi-line. =end ``` Names are all lowercase and words are separated with `_`. ```ruby large_number = 7893425089273045 player_name = "Jimothy" ``` ## Concept Intro ```ruby puts("Hello, World!") ``` # Section Intro ## Concept Intro ```ruby puts("Hello, World!") ``` # MongoDB After installing MongoDB and loading into the database, (or another from ,) > Thank you for reading! > Find more content at > Source page: > Site index: [llms.txt](https://manuals.ryanfleck.ca/llms.txt)