我试图遵循Hartl的Rails教程，但在第二章遇到问题。
I'm at this section并在此之前做所有事情......
$ rails server -b $IP -p $PORT # Use only `rails server` if running locally
它给了我一个错误......
/home/carson/.rvm/rubies/ruby-2.2.5/lib/ruby/2.2.0/socket.rb:232:in `getaddrinfo': getaddrinfo: Name or service not known (SocketError)
from /home/carson/.rvm/rubies/ruby-2.2.5/lib/ruby/2.2.0/socket.rb:232:in `foreach'
from /home/carson/.rvm/rubies/ruby-2.2.5/lib/ruby/2.2.0/socket.rb:459:in `tcp_server_sockets'
from /home/carson/.rvm/rubies/ruby-2.2.5/lib/ruby/2.2.0/webrick/utils.rb:70:in `create_listeners'
from /home/carson/.rvm/rubies/ruby-2.2.5/lib/ruby/2.2.0/webrick/server.rb:133:in `listen'
from /home/carson/.rvm/rubies/ruby-2.2.5/lib/ruby/2.2.0/webrick/server.rb:114:in `initialize'
from /home/carson/.rvm/rubies/ruby-2.2.5/lib/ruby/2.2.0/webrick/httpserver.rb:45:in `initialize'
from /home/carson/.rvm/gems/ruby-2.2.5/gems/rack-1.6.4/lib/rack/handler/webrick.rb:31:in `new'
from /home/carson/.rvm/gems/ruby-2.2.5/gems/rack-1.6.4/lib/rack/handler/webrick.rb:31:in `run'
from /home/carson/.rvm/gems/ruby-2.2.5/gems/rack-1.6.4/lib/rack/server.rb:286:in `start'
from /home/carson/.rvm/gems/ruby-2.2.5/gems/railties-4.2.6/lib/rails/commands/server.rb:80:in `start'
from /home/carson/.rvm/gems/ruby-2.2.5/gems/railties-4.2.6/lib/rails/commands/commands_tasks.rb:80:in `block in server'
from /home/carson/.rvm/gems/ruby-2.2.5/gems/railties-4.2.6/lib/rails/commands/commands_tasks.rb:75:in `tap'
from /home/carson/.rvm/gems/ruby-2.2.5/gems/railties-4.2.6/lib/rails/commands/commands_tasks.rb:75:in `server'
from /home/carson/.rvm/gems/ruby-2.2.5/gems/railties-4.2.6/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
from /home/carson/.rvm/gems/ruby-2.2.5/gems/railties-4.2.6/lib/rails/commands.rb:17:in `<top (required)>'
from /home/carson/Ruby/rortutorial/toy_app/bin/rails:9:in `require'
from /home/carson/Ruby/rortutorial/toy_app/bin/rails:9:in `<top (required)>'
from /home/carson/.rvm/gems/ruby-2.2.5/gems/spring-1.7.1/lib/spring/client/rails.rb:28:in `load'
from /home/carson/.rvm/gems/ruby-2.2.5/gems/spring-1.7.1/lib/spring/client/rails.rb:28:in `call'
from /home/carson/.rvm/gems/ruby-2.2.5/gems/spring-1.7.1/lib/spring/client/command.rb:7:in `call'
from /home/carson/.rvm/gems/ruby-2.2.5/gems/spring-1.7.1/lib/spring/client.rb:30:in `run'
from /home/carson/.rvm/gems/ruby-2.2.5/gems/spring-1.7.1/bin/spring:49:in `<top (required)>'
from /home/carson/.rvm/gems/ruby-2.2.5/gems/spring-1.7.1/lib/spring/binstub.rb:11:in `load'
from /home/carson/.rvm/gems/ruby-2.2.5/gems/spring-1.7.1/lib/spring/binstub.rb:11:in `<top (required)>'
from /home/carson/Ruby/rortutorial/toy_app/bin/spring:13:in `require'
from /home/carson/Ruby/rortutorial/toy_app/bin/spring:13:in `<top (required)>'
from bin/rails:3:in `load'
from bin/rails:3:in `<main>'
我真的不太了解......实际调试这个或从哪里开始，有什么帮助？