#install ruby

Will write up a better documentation of download process later!

https://rvm.io

$ sudo apt-get update

$ sudo apt-get install build-essential openssl libreadline6 libreadline6-dev curl git-core zlib1g zlib1g-dev libssl-dev libyaml-dev libsqlite3-dev sqlite3 libxml2-dev libxslt-dev autoconf libc6-dev ncurses-dev automake libtool bison subversion pkg-config libgdbm-dev libffi-dev libreadline-dev $ curl -L https://get.rvm.io | bash -s stable $ echo 'source ~/.rvm/scripts/rvm' >> ~/.bash_aliases && bash

Install the versions of Ruby you need. I installed -

$ rvm install 2.0.0-p247

I'm running Ubuntu 13.04 and installed RVM to manage my Ruby versions.  

1.9.3 was the only version that I could get to install without 'make' errors. I found that running the following set of commands corrected my issue and I now have 1.8.7,  1.9.1,  1.9.2, 1.9.3,  and 2.0 successfully installed.  Maybe this will save someone my headache.

rvm get head rvm reload rvm remove <insert ruby version>

I recently posted a blog about install ruby on ubuntu. I was wrong there is a lot better way to install Ruby on linux and OS X and that is to use RVM.

RVM (Ruby Version Manager) allows you to manage multiple sets of ruby environments on the one machine. It is the most awesome thing in the world ever. 

I have used it now to install ruby on multiple machines both Ubuntu based and OS X. 

Here is a quick run down on using RVM the first thing is you are going to need is to install some prerequisites list below. (by the way I just want to say that RVM works on other Linux flavours but I haven't installed it on anything but ubuntu!)

Ubuntu 

You will need to install build-essential , this is basically all the stuff need to compile code. you can get it with 

sudo apt-get install build-essential

next you will need GIT (yeah I don't get the giant tree eating monster ether) and CURL. If you have been living under a rock then git is a distributed version control system and more than likely the best version control system out there. Curl is a command line tool to interact with URL's, you can get them both at once with

sudo apt-get install git-core curl

And your system is ready for RVM.

OS X

Ok Mac users you will need to get Xcode this is because it includes apples version of build essentials. You can get it from the new App store or here http://developer.apple.com/xcode/index.php. The other thing you are going to need is GIT. Go to http://git-scm.com/ and download Git for OS X and install it. Don't worry you wont get an Icon. Your lucky you should already have curl. 

And Your System is ready for RVM.

Back To Both

Next you will need to get RVM , open a console and type ( or copy+paste ) this 

bash < <(curl -s https://rvm.beginrescueend.com/install/rvm)

That will install RVM for you if you want to know what is doing or worry about sending scripts straight to be executed you can check it out here https://rvm.beginrescueend.com/rvm/install/.

Once its finished you will need to install it in to your .profile , .bash_profile or .bashrc file so that you can access RVM from anywhere you need. 

[[ -s "$HOME/.rvm/scripts/rvm" ]] && source "$HOME/.rvm/scripts/rvm" # Load RVM into a shell session *as a function*

We are almost ready to install ruby but first we need to make sure that your computer can build the MRI and GEM. This is easy as RVM has a function to tell us what we need. To see use the command 

rvm notes

This will list all the dependencies that you will need to build ruby(MRI & Ree). On OS X you should just need to make sure that you have Xcode installed. On Ubuntu you will end up with something like 

sudo apt-get install build-essential bison openssl libreadline6 libreadline6-dev curl git-core zlib1g zlib1g-dev libssl-dev libyaml-dev libsqlite3-0 libsqlite3-dev sqlite3 libxml2-dev libxslt-dev autoconf libc6-dev ncurses-dev

Don't worry about whether you have some off these installed already as APT-GET is smart enough to just not reinstall them

Right now the fun bit installing ruby (yeah Finally but its worth it)

rvm install 1.9.2

If there is a new version of ruby ( the current was 1.9.2) or you want an older version of ruby i.e 1.8.x then replace the version number. After a while RVM will finish building and install ruby and ruby gem. As I said earlier RVM can manage multiple environments so to set the one you just installed to be the default and to use it you need to run the command

rvm use --default 1.9.2

(If you installed a different version number then simply replace the 1.9.2 with the version you installed)

You should now be up and running with ruby, you can check by doing the old

ruby -v gem -v