我有一个Ruby脚本，试图要求restclient模块。当我将它简化为仅有这一行时，它仍然失败：
#!/usr/bin/env ruby
require 'restclient'
当我运行它时，出现以下错误：
./test.rb:3:in `require': no such file to load -- restclient (LoadError)
from ./test2.rb:3
当我运行irb时，模块可以正常加载：
$ irb
>> require "restclient"
=> true
>>
据我所知，脚本和irb看起来具有相同的模块路径：
$ 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
>>
为什么一个模块可以在irb中加载，但是直接运行Ruby却不能？
还有一个令人困惑的细节是，restclient gem似乎不在我的路径中。那么irb是如何找到它的呢？
$ 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
感谢您 - Marc