From: Eric Hodel <drbrain@...7.net>
Date: 2008-05-29T04:17:31+09:00
Subject: Re: ruby-opengl gem uses ruby1.9, even from gem1.8

On May 28, 2008, at 03:24 AM, David Masover wrote:
> On Wednesday 28 May 2008 03:55:32 Eric Hodel wrote:
>> On May 28, 2008, at 01:14 AM, David Masover wrote:
>>> This is on an Ubuntu Hardy system, on x86_64. Both Ruby 1.8 and 1.9
>>> are installed.
>>>
>>> I was tracking down the lack of ruby.h, which surprised me, as
>>> ruby1.8-dev is installed. Scrolling up even further, though, and  
>>> something just
>>> seems wrong about these three lines:
>>>
>>> rake RUBYARCHDIR=/var/lib/gems/1.8/gems/ruby-opengl-0.60.0/lib
>>> RUBYLIBDIR=/var/lib/gems/1.8/gems/ruby-opengl-0.60.0/lib extension
>>> /usr/bin/ruby1.9 mkrf_conf.rb
>>> (in /var/lib/gems/1.8/gems/ruby-opengl-0.60.0)
>>>
>>> Why is ruby1.9 being used to run mkrf_conf.rb? I am using a 1.8 gem
>>> -- as you
>>> can see, it's trying to install in a 1.8 path, and:
>>>
>>> $ head -1 `which gem`
>>> #! /usr/bin/ruby1.8
>>> $ head -1 `which gem1.9`
>>> #!/usr/bin/ruby1.9
>>
>> head -1 `which rake`
>
> Ah. Thanks:
>
> $ head -1 `which rake`
> #!/usr/bin/ruby1.9
>
> After installing rake via gem1.8, I still get the same on rake and  
> rake1.9 --
> but they are not the same file:
>
> $ diff /usr/bin/rake /usr/bin/rake1.9
> 1a2,4
>>
>> #--
>> # Copyright (c) 2003, 2004, 2005, 2006, 2007  Jim Weirich

They should have a different shebang line.  Re-run `gem install rake`  
again to make plain `rake` be the 1.8 one.

You may want to add "install: --format-executable" to your ~/.gemrc to  
make gem add 1.8 or 1.9 to gem executable names so that they don't  
step on each others' toes.