Ruby

Installation on Ubuntu

• https://www.ruby-lang.org/en/documentation/installation/
• apt-get install ruby will install v1.8 or v1.9. v1.8 is kind of old that nokogiri, for example, cannot be installed.
• I tried to install from the source (v2.2.1) on Ubuntu 14.04. The canonical method ./configure, make & sudo make install does not work at 'make' step. # See https://github.com/sstephenson/ruby-build/issues/690. Unfortunately the method of installing libffi-dev does not solve the error on Ubuntu 14.0.
• The next method is ruby-build. Don't quite follow it.

http://stackoverflow.com/questions/26595620/how-to-install-ruby-2-1-4-on-ubuntu-14-04 mentioned a couple of methods.

• rbenv method. Not sure if it works since the shell hangs when I run 'rbenv install 2.2.0'.
• rvm (ruby version manager) method.

sudo apt-get update
sudo apt-get install build-essential make curl
\curl -L https://get.rvm.io | bash -s stable
source ~/.bash_profile
# sudo apt-get install ruby-rvm
time rvm install ruby-2.1.4

The last step will take a while (27 minutes in my case) since no binary rubies for my OS/architecture were available and it has to compile Ruby from the source. At the end of installing, it will show

Install of ruby-2.1.4 - #complete 
Ruby was built without documentation, to build it run: rvm docs generate-ri

Then check ruby versions installed and in use

which rvm
# /home/brb/.rvm/bin/rvm
ruby -v
# ruby 2.1.4p265 (2014-10-27 revision 48166) [x86_64-linux]
which gem
# /home/brb/.rvm/rubies/ruby-2.1.4/bin/gem
rvm list
rvm use --default ruby-2.1.4

Documentation

• https://www.ruby-lang.org/en/documentation/
• Ruby in 20 minutes from ruby-lang.org.

Install Gems

# sudo apt-get install rubygems
gpg --keyserver hkp://keys.gnupg.net --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3
\curl -L https://get.rvm.io | bash -s stable
source ~/.bash_profile
time rvm install ruby-2.1.4
rvm list
which ruby
gem install nokogiri

$ gem install nokogiri
Building native extensions.  This could take a while...
Successfully installed nokogiri-1.6.6.2
Parsing documentation for nokogiri-1.6.6.2
Done installing documentation for nokogiri after 2 seconds
1 gem installed