How to tell Terminal which version of Ruby to use?

Question

Hello,

I have two related questions that I was hoping someone could help out with.

1. I recently installed Ruby 1.9.2 on my Mac (running Snow Leopard 10.6.4) and I haven’t been able to figure out how to get Terminal to use the new Ruby as a default, rather than the factory-installed Ruby 1.8.7. The old Ruby 1.8.7 is located in my ~/usr/bin/ruby directory while the new Ruby 1.9.2 is in ~/usr/local/bin/ruby. Someone said that I need to put the new version of Ruby's directory in the PATH prior to the old version's directory so that the system looks there first - is this correct? If so, can anyone provide step by step instructions on how to do this?

2. I’ve created a new directory but can’t seem to figure out the correct way to add that directory to my PATH using the Terminal bash shell. I tried using the instructions that I found here (http://www.macgasm.net/2008/04/10/ad...thin-terminal/) twice but they didn't work for me. The directory containing my program ("Ruby_Programs") shows up in the PATH but when I try to run "ruby newprogram.rb" from the command line it results in ":ruby: No such file or directory -- newprogram.rb (LoadError)". The file definitely exists and is a functional Ruby program. I did change the name of the directory to "Ruby Programs" and then back to "Ruby_Programs" - could that have somehow caused this problem?

Any help would be greatly appreciated. Here is my current PATH:

$ echo $PATH /usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/Users/sbrriffe/src:/usr/X11/bin:/Users/sbriffe/Ruby_Programs/:

Answer 1

Your Ruby Programs directory shouldn't be in your path: the location of your ruby interpreter should be. Then, you cd to the location of your ruby program, and run it from there: ruby program.rb.

Since you are on a Mac, check out homebrew for something that will make installing software easier. I have my homebrew set up in /usr/local, and it works great.

Once you have installed stuff where you need it, then you'll want to adjust your $PATH. The items in $PATH are searched in the order they appear, so in your ~/.bashrc, you'll want to add:

export PATH=/usr/local/bin:$PATH

To make sure /usr/local/bin gets searched before /usr/bin.

Answer 2

You might want to check out rvm. You can install multiple versions of ruby side by side and easily switch between them. If you follow the rvm installation notes you won't have any more path problems.