Alex Tamoykin - Start Programming Now: No CS Degree Needed

Package manager is a program that installs and manages different packages. Ubuntu already has a built in package manager called apt-get. On Mac OS X youll need to download Homebrew. Open up the program named Terminal and execute this script to install it:

Were going to use the database called PostgreSQL aka Postgres. Its simple to install and use. Its supported by many platforms. Lets install it using Homebrew. Well also configure Postgres to run locally.

Following commands make it so Postgres starts up on boot. Its convenient. You wont need to start it manually every time you reboot.

Now its time to create a database user for our application.

Now is time to install Rails framework. Rails is distributed as a ruby gem. RubyGems is a packaging system that comes with ruby installation. Well need to use gem command to install it

I recommend to start with RubyMine. I used it myself to start with. It does a lot of stuff for you automatically so you can focus on learning how to program instead of configuring your development environment. Download and install the 30 days trial from JetBrains Downloads

Congratulations! Now you have all necessary software to start programming. Cant wait to write a first line of code ? Lets learn how to do it.

Dont be scared of coding. Its actually pretty simple. Look at

Figure 3.1: How Programming Works

Any program is just code running by an interpreter inside an operating system. Let me explain:

1. Code is text written according to a certain (Ruby) syntax which is stored into a regular file.
2. Interpreter (Ruby binary) is the program that reads code and runs it. It takes some actions according to instructions written in code.
3. Operating System (Mac OS X) is the software installed on our computer that runs the interpreter.

Thats it! So all we need to do is to write some ruby code and run it. Lets figure out how to write code.

Variables are like labels. Lets say you put all your old stuff in a box. You dont want to forget whats in it. You put a label on the box with the name old_stuff. Next time you want to look at your old stuff, you can refer to the box named old_stuff. Same analogy works for programming. You create a variable named old_stuff. You assign it a value of action figures of Ninja Turtles which is a string of text. When you need to look at old_stuff in your program, you can reference it by the variable named old_stuff.

old_stuff = "action figures of Ninja Turtles" puts "My old stuff is " + old_stuff

Box 3.1. Variable naming convention

Every programming language has its own convention. Its a set of naming rules that programmers agree to use for the sake of consistency. Here is our first Ruby convention. A variable name in Ruby is always lowercase separated with the underscore symbol. For instance: