RubyBuntu -1- Installing Ruby (and Rails) on ubuntu

Installing Ruby/Rails on ubuntu is not hard, but some little obstacles might be confusing.

This guide has been tested on ubuntu 10.04 “Lucid Lynx”, ubuntu 10.10 “Maverick Meerkat” and ubuntu 11.04 “Natty Narwhal”, but should also work for other debian based linux distors.

The debian dilemma

Unfortunately, on debian and ubuntu, the whole Ruby installation is split into different packages. When installing the ruby package, some parts of Ruby are not installed, for example irb or ri.

Although there is a way to install all Ruby packages with the command sudo apt-get install ruby-full, I would not recommend it. Besides getting some emacs packages (?), one (at least me) quickly loses the overview about which packages are installed and which are not..

The recommended way to install Ruby is using the Ruby Version Manager (RVM). If you do not want to depend on external scripts you must choose one of these two ways: Either using the ubuntu repositories, or building Ruby from source. You should try to not mix these approaches!

Option 0: Use Ruby Version Manager

Use this option, if there is no reason, why you should use one of the other ways ;)

RVM makes it easy to install multiple rubies and switch between them.

sudo apt-get install curl git-core
bash < <(curl -s https://rvm.beginrescueend.com/install/rvm)

Add this to your ~/.bashrc (this step is not needed in newer versions of rvm):

[[ -s "$HOME/.rvm/scripts/rvm" ]] && source "$HOME/.rvm/scripts/rvm"

Then restart your terminal or enter: source ~/.bashrc

Now, Ruby can be installed with:

sudo apt-get install libruby1.8 libruby1.9 zlib1g-dev libssl-dev libreadline-dev build-essential
rvm install ruby-1.9.3
rvm use ruby-1.9.3 --default

Please note: Do not use sudo for installing gems!

Information about how to install different versions can be found by entering rvm notes

Ruby is ready now :). More information about rvm+bundler can be found in this blog article

Option 1: Install Ruby 1.8 from the ubuntu repositories

This way is recommended, if you just want to have a working version of Ruby and do not care about the details.

The disadvantage (or advantage?) of this approach is that you depend on the ubuntu package maintainers. They decide, when to upgrade. They decide, what name schema and directory structure is used.

Anyway, first of all, you should add the ubuntu-on-rails ppa repository, sometimes they have newer versions of some Ruby components. Do it by typing:

sudo add-apt-repository ppa:ubuntu-on-rails
sudo apt-get update

Now get the essential ruby packages:

sudo apt-get install ruby rubygems irb ri rdoc rake

The dependencies should look like:
irb1.8 libreadline-ruby1.8 libreadline5 libruby1.8 rdoc1.8 ri1.8 ruby1.8 rubygems1.8

But you need more packages!

sudo apt-get install build-essential ruby1.8-dev libopenssl-ruby

These extra packages are very important – odds are high that you will need them. Unfortunately they are not in the standard package dependencies, partly because of some licensing issues – readline and openssl have incompatible licenses.

After getting all packages, there is another little step necessary: You have to add the gem path to your global PATH, so that executables new gems can be easily called from the command line. Do it by adding the following line to your ~/.bashrc:

export PATH=/var/lib/gems/1.8/bin:$PATH

Then restart your terminal or enter source ~/.bashrc

Ruby is ready now :)

A little side note: Because of a safety restriction of ubuntu, sudo does not work with executables of gems. Usually you don’t need sudo these, but exceptions might occur. To enable it, add the gem bin path to the the global /etc/bash.bashrc and apply this workaround.

Option 2: Build it from source

This way is recommended, when you want to have full control over your installation.

Do not get deterred, it is not that hard. Firstly, get the needed dev packages:

sudo apt-get install libruby1.8 libruby1.9 zlib1g-dev libssl-dev libreadline-dev build-essential

Now get fresh sources from the official web page. For 1.8, you also need a recent version of rubygems from rubygems.org. Either download and extract them manually, or use the following lines:

1.9

@wget https://ftp.ruby-lang.org/pub/ruby/1.9/ruby-1.9.3-p0.tar.gz

tar -xzf ruby-1.9.3-p0.tar.gz

1.8

wget ftp://ftp.ruby-lang.org/pub/ruby/1.8/ruby-1.8.7-p334.tar.gz
wget https://production.cf.rubygems.org/rubygems/rubygems-1.8.5.tgz
tar -xzf ruby-1.8.7-p334.tar.gz
tar -xzf rubygems-1.8.5.tgz

Now navigate to the extracted ruby directory and run:

./configure
make
sudo make install

To install both versions at the same time (without RVM), you can pass a --program-suffix option to one of the ./configure commands before compiling.

You can check if this was successful with: ruby -v

Optional: Install the ruby documentation (used by ri) with: sudo make install-doc

In 1.9, you should also update rubygems: sudo gem update --system

For 1.8, change to the extracted rubygems-1.6.2 directory and run:

sudo ruby setup.rb

Ruby is ready now :).

Install your gems

You should rarely (never) install gems from the ubuntu repositories (apt-get), but those from the gem repository. However, sometimes you need some additional library packages. If the installation of a gem fails, you often just need to install the right libXXXX or XXXX-dev package, and it suddenly works. To find out which one, use the ubuntu package search or your search engine.

Rails

Choose a database, for example sqlite3

sudo apt-get install sqlite3 libsqlite3-dev
sudo gem install sqlite3-ruby

or MySQL

sudo apt-get install mysql-server libmysqlclient-dev
sudo gem install mysql

and install the framework:

sudo gem install rails

Done

def encountered_errors?
  check_out common_problems!
else
  start_to have_fun! # :)
end