From: Markus Schirp <mbj@...>
Date: 2010-09-14T17:36:08+09:00
Subject: Re: How to tell Terminal which version of Ruby to use?

I suffered from similar problems in the past. Now I'm a big fan of the 
tool rvm. It helps you to install and switch between your rubies.

Im unsure weather it works on mac, but you can give it a try:

http://rvm.beginrescueend.com



On 09/14/2010 10:16 AM, Sam Riffe wrote:
> Hello,
>
> I have two entry level 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?
>
> [Side Note: I actually somehow got it to work when I first installed
> 1.9.2, but I have networked computers and a wireless Apple Time Machine
> backing up both machines that is somehow communicating shell settings
> via the backup mechanism, from my un-upgraded MacBook back to the iMac
> that has the new 1.9.2 installed.  Somehow the PATH settings from the
> MacBook seems to be overriding what's on the iMac.  I've noticed the
> same thing happens with my TextMate preferences - the style preferences
> on the laptop get transferred to the one on the iMac in realtime
> somehow.  After I figure out how to fix this, I'm going to change the
> shell settings on both machines to try and prevent this.  Just curious
> if others have encountered this issue.]
>
> 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/:
>
>
> 3. I can't get the shebang line to work in any of my Ruby programs.  Is
> there a specific permission that needs to be set on Mac files to get the
> shebang line to work?  It points to the right directory that contains
> the Ruby interpreter and it's supposed to be a fairly simple line of
> code, but I'm never able to run Ruby programs in the shell without the
> "ruby" preface in the command line.
>
> Thanks in advance.