我可以安装gem ruby-debug，但是rails服务器找不到它

Question

我在安装ruby gem时发现了一个非常有趣的问题。

bluehat@Matapan:~/code/Amacron$ rails server --debugger
=> Booting WEBrick
=> Rails 3.0.3 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
You need to install ruby-debug to run the server in debugging mode. With gems, use 'gem install ruby-debug'
Exiting
bluehat@Matapan:~/code/Amacron$ sudo gem install ruby-debug
Successfully installed ruby-debug-0.10.4
1 gem installed
Installing ri documentation for ruby-debug-0.10.4...
Installing RDoc documentation for ruby-debug-0.10.4...
bluehat@Matapan:~/code/Amacron$ rails server --debugger
=> Booting WEBrick
=> Rails 3.0.3 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
You need to install ruby-debug to run the server in debugging mode. With gems, use 'gem install ruby-debug'
Exiting
bluehat@Matapan:~/code/Amacron$ sudo gem update ruby-debug
Updating installed gems
Nothing to update
bluehat@Matapan:~/code/Amacron$ gem --version
1.3.7
bluehat@Matapan:~/code/Amacron$ rails --version
Rails 3.0.3

系统是最新的Ubuntu 11.04

Answer 1

你把这个gem放到你的应用程序的Gemfile里了吗？

Answer 2

我通过安装irb包解决了这个问题。错误消息是关于ruby-debug的，但是一旦我安装了debian packed for irb，一切都是正常的。

Answer 3

我也有同样的问题。原因是在应用程序的Gemfile中，行"gem 'ruby-debug'“被注释掉了。我启用了这一行，一切工作正常。