There seems to be two threads associated with this topic - perhaps
someone can merge them.
The easiest way to use JRuby complete - assuming the JVM is already
installed is to create a directory structure for your program project
Put a copy of jruby-complete-xxx.jar into lib
Create a shell script (I call mine localTerminal.sh) in the project
directory with this content
As far as I know a similar .bat file will work on Windows
Just for convenience make another shell script called JRUBY with this in
java -jar lib/jruby-complete-1.7.0.jar $*
When you double-click the shell script it opens a terminal at the
project directory and then you can run your program with JRUBY myprog.rb
and you can list gems and do all the other stuff with JRUBY -S gem list.
Once you have created this framework you can just copy it somewhere else
to start another project.
No need for RVM or Bundler or any of that stuff - JRuby makes Ruby