Do ruby and irb use different module search paths?

Question

I have a Ruby script that is trying to require the restclient module. When I reduce it down to just this one line, it still fails:

#!/usr/bin/env ruby

require 'restclient'

When I run it, I get the following error:

./test.rb:3:in `require': no such file to load -- restclient (LoadError)
    from ./test2.rb:3

When I run irb, the module loads fine:

$ irb
>> require "restclient"
=> true
>>

As far as I can tell, it looks like both the script and irb have the same module paths:

$ ruby -e "puts $:"
/Library/Ruby/Site/1.8
/Library/Ruby/Site/1.8/powerpc-darwin10.0
/Library/Ruby/Site/1.8/universal-darwin10.0
/Library/Ruby/Site
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/vendor_ruby/1.8
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/vendor_ruby/1.8/universal-darwin10.0
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/vendor_ruby
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/powerpc-darwin10.0
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/universal-darwin10.0
.

$ irb
>> puts $:
/Library/Ruby/Site/1.8
/Library/Ruby/Site/1.8/powerpc-darwin10.0
/Library/Ruby/Site/1.8/universal-darwin10.0
/Library/Ruby/Site
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/vendor_ruby/1.8
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/vendor_ruby/1.8/universal-darwin10.0
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/vendor_ruby
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/powerpc-darwin10.0
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/universal-darwin10.0
.
=> nil
>>

What would cause a module to load through irb, but not when run directly through Ruby?

One other confusing detail is that the restclient gem doesn't seem to be in my path to start with. How is irb finding it?

$ locate restclient | grep gems
/Library/Ruby/Gems/1.8/gems/rest-client-1.6.1/bin/restclient
/Library/Ruby/Gems/1.8/gems/rest-client-1.6.1/lib/restclient
/Library/Ruby/Gems/1.8/gems/rest-client-1.6.1/lib/restclient/abstract_response.rb
/Library/Ruby/Gems/1.8/gems/rest-client-1.6.1/lib/restclient/exceptions.rb
/Library/Ruby/Gems/1.8/gems/rest-client-1.6.1/lib/restclient/net_http_ext.rb
/Library/Ruby/Gems/1.8/gems/rest-client-1.6.1/lib/restclient/payload.rb
/Library/Ruby/Gems/1.8/gems/rest-client-1.6.1/lib/restclient/raw_response.rb
/Library/Ruby/Gems/1.8/gems/rest-client-1.6.1/lib/restclient/request.rb
/Library/Ruby/Gems/1.8/gems/rest-client-1.6.1/lib/restclient/resource.rb
/Library/Ruby/Gems/1.8/gems/rest-client-1.6.1/lib/restclient/response.rb
/Library/Ruby/Gems/1.8/gems/rest-client-1.6.1/lib/restclient.rb
/Library/Ruby/Gems/1.8/gems/rest-client-1.6.1/spec/restclient_spec.rb

Thanks - Marc

Answer 1

Try

require "rubygems"

in the source code file, or starting the ruby program with ruby -rubygems filename.rb.