RVM

It looks like I am the last hold out for the use of RVM.  What prompted my move?  Well Macs come with ruby 1.8.7, but I always use ruby 1.9 in my projects.  I replaced the standard system ruby with my own 1.9 version.  The problem came when starting a new job since they used ruby 1.8.7 (a patch level greater then supplied my Apple), and JRuby.

I spend a few hours just trying to get JRuby to play nice with the 1.9 version that I had installed.  Things where not going well.  The problems were almost entirely related to path-ing, but I am ruby programer not a system administrator.  I was almost ready to give up when I remembered a lightning talk given at the B'more on Rails group on RVM.

In case you, like me, have been hiding under a rock for the last few years RVM is a Ruby Version Manager.  In a nutshell it lets you install any or all versions of ruby in their own sandbox (you would be insane to install "all", but you can!).  It solves all the problems associated with having different ruby versions installed and allows you to easily switch ruby versions with rvm use XXX where XXX is the version of ruby of you want.

More then just being able to switch ruby versions; you are able to create arbitrary sandboxes for gems called GemSets.  This is most useful for me in trying to figure out what gems are used in what projects.  In most of my projects now I have a .rvmrc files containing the version of ruby and the GemSet to use for that project: echo "rvm use XXX@YYY --create" > .rvmrc, where XXX is the ruby version and YYY is the GemSet to use.  --create just creates a GemSet if it doesn't exist.

Your results may vary, but for me all I had to do was:

1. Follow the quick install: bash < <( curl http://rvm.beginrescueend.com/releases/rvm-install-head )
2. List the rubies I could install: rvm list known
3. Install a few rubies: rvm install XXX
4. Switch to a ruby and test it: rvm use XXX
5. Setup and a .rvmrc file: echo "rvm use XXX@YYY --create" > .rvmrc

I have not yet played around enough to see if I could use a GemSet to create a Bundler package.  It seems that they are made to play nice with each other, so I foresee no reason it will not be as straight forward as this.