Sometme I found the different concepts in Ruby very confusing for beginners. So I write this post to explain some terminologies in ruby setup.

RubyGems (tool)

RubyGems is a package manager for the Ruby programming language.

It is a tool to manage the installation of gems, and a server for distributing them.

RubyGems is very similar to apt-get, portage, and yum in functionality.

gem (command)

‘gem’ command allows you to interact with RubyGems. It is used build, upload, download, and install Gem packages.

Installation:

gem install mygem

Uninstallation:

gem uninstall mygem

Listing installed gems:

gem list --local

Listing available gems, e.g.:

gem list --remote

Gemfile (text file)

A Gemfile describes the gem dependencies required to execute associated Ruby code.

It is placed in the root of the directory containing the associated code.

A Gemfile is evaluated as Ruby code, in a context which makes available a number of methods used to describe the gem requirements.

gem (program)

ref1, ref2

A gem is a module/Library that you can install and use in every project on your server.

Each gem has a name, version, and platform. For example, rake gem has a 10.3.2 version on platform Ruby.

Inside a gems are the following components:

1. Code (including tests and supporting utilities)
2. Documentation
3. gemspec

Standard code structure:

% tree freewill
freewill/
├── bin/
│   └── freewill
├── lib/
│   └── freewill.rb
├── test/
│   └── test_freewill.rb
├── README
├── Rakefile
└── freewill.gemspec

Bundler (dependency manager)

ref

Bundler manages an application’s dependencies.

Bundler provides a consistent environment for Ruby projects by tracking and installing the exact gems and versions that are needed.