Apple meant well when they pre-installed Ruby on Rails and a few gems. But since they didn’t keep up to-date with the fast pace of development at least Rails and a few gems are heavily outdated.

You basically have two options to proceed if you want to get a reasonable modern RoR installation on your Macintosh:

You go the long and hard way: Install XCode and all the developer tools Apple supplies (2+ GB), and follow this excellent tutorial in building everything from scratch and leaving the RoR installation Apple supplied in pristine state.

Take the ’small-footprint-approach’ and tackle possible problems later (IF Apple to decides to update the system as well and IF this causes trouble). This is the route I chose and here is how it goes without any problems or errors:

• sudo gem update –system
• sudo gem update rails –include-dependencies

Basically what happens is, the first command updates the Ruby gem system and gems; the second command updates the Rails installation to, currently, 2.1.2. Something you are not getting is an updated SQLITE gem, because the native extensions can’t be built. But if you are working with a remote MySQL server this is no problem.

Also check out these slightly outdated instructions from Apple on this topic: Developing Rails Applications on Mac OS X Leopard.