Installing system jruby for ruby processing

Windows and Mac

For Windows and Mac users you could probably do much worse than following Jruby.org instructions.

Linux

For most linux users RVM will be a pain, and further the distro supplied version of ruby-processing will be hopelessly out of date (with the exception of ArchLinux).

ArchLinux

Installation is a simple as

sudo pacman -Syu # make sure you are up to date
sudo pacman -S jruby # currently installs jruby-1.7.4, you can ignore issue with ffi that has been fixed since

You need to be aware your gems will get installed which is {USER.HOME}/.gem/ruby/2.0.0, best to set GEM_HOME environment in your .bashrc, and add ${GEM_HOME}/bin to your path as well (now you gem installed executables should run).

Ubuntu and other debian flavours

Download and unzip tarball into /opt (well that is conventionally where such packages live), create a symbolic link to jruby executable using update alernatives as follows:-

sudo update-alternatives --install /usr/bin/jruby ruby /opt/jruby-1.7.4/bin/jruby 100

On ubuntu/kubuntu at least you usually need sudo to install gems, and they get installed in /var/lib/gems/1.9.1 so you might like to set GEM_HOME and PATH appropriately. To be sure probably best to install ruby-processing and any other gems you might like to use using:-

sudo jruby -S gem install my_gem.gem