From: Eric Hodel <drbrain@...7.net>
Date: 2010-04-01T12:14:30+09:00
Subject: Re: Rubygems update breaks other gems?

On Mar 27, 2010, at 02:00, kgthegreat wrote:
Hello,
> 
> I am on Ubuntu 9.10
> I ran the following commands for a rubygems update from 1.3.5 to 1.3.6
> 
> $  sudo gem install update_rubygems
> $  cd /var/lib/gems/1.8/bin
> $  sudo ./update_rubygems
> $  gem -v
> 1.3.6

Had you run `gem update --system` it would have said something like "don't do that" because you (probably) have debian/ubuntu RubyGems installed.

> but after this some of the installed gems fail to work . For eg.
> 
> $  rails -v
> /usr/local/lib/site_ruby/1.8/rubygems.rb:777:in
> `report_activate_error': Could not find RubyGem rails (>= 0)
> (Gem::LoadError)
> 	from /usr/local/lib/site_ruby/1.8/rubygems.rb:211:in `activate'
> 	from /usr/local/lib/site_ruby/1.8/rubygems.rb:1056:in `gem'
> 	from /var/lib/gems/1.8/bin/rails:18
> 
> What is wrong here?

ubuntu/debian RubyGems and standard RubyGems disagree with each other.  Now that you've installed standard RubyGems you'll need to set the GEM_HOME environment variable to /var/lib/gems/1.8, I think