railstutorial.org gems/notiffany-0.1.1/lib/notiffany/notifier/tmux/client.rb:12:在“版本”中：未定义的方法
railstutorial.org gems/notiffany-0.1.1/lib/notiffany/notifier/tmux/client.rb:12:in `version': undefined method
我正在 RailsTutorial.org 上的 Rails 教程中学习 Ruby，并且正在学习第 3.3.1 节 (/book/static_pages#cha-static_pages) 运行 'rails test' 第一次。我根据建议使用 Cloud9 IDE，据我所知，我完全按照脚本进行了操作。一切都匹配到这一点。
我也对错误进行了一些搜索，并提出了关于 tmux 的评论，但我在 Ruby on Rails 或 Cloud9 方面经验不足，无法确定是什么我正在做。有人还建议使用 'bundle exec rake test' 作为替代方法，但我得到了同样的错误：
2 runs, 2 assertions, 0 failures, 0 errors, 0 skips
/usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/tmux/client.rb:12:in 'version': undefined method '[]' for nil:NilClass (NoMethodError)
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/tmux.rb:69:in '_check_available'
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/base.rb:59:in 'initialize'
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/detected.rb:100:in 'new'
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/detected.rb:100:in '_add'
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/detected.rb:62:in 'block (2 levels) in detect'
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/detected.rb:60:in 'each'
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/detected.rb:60:in 'detect'
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/detected.rb:60:in 'block in detect'
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/detected.rb:59:in 'each'
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/detected.rb:59:in 'detect'
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier.rb:180:in '_detect_or_add_notifiers'
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier.rb:198:in '_activate'
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier.rb:87:in 'initialize'
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier.rb:42:in 'new'
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier.rb:42:in 'connect'
from /usr/local/rvm/gems/ruby-2.4.1/gems/guard-2.13.0/lib/guard/notifier.rb:11:in 'connect'
from /usr/local/rvm/gems/ruby-2.4.1/gems/guard-2.13.0/lib/guard/notifier.rb:31:in 'notify'
from /usr/local/rvm/gems/ruby-2.4.1/gems/guard-compat-1.2.1/lib/guard/compat/plugin.rb:113:in 'notify'
from /usr/local/rvm/gems/ruby-2.4.1/gems/guard-minitest-2.4.4/lib/guard/minitest/notifier.rb:31:in 'notify'
from /usr/local/rvm/gems/ruby-2.4.1/gems/guard-minitest-2.4.4/lib/guard/minitest/reporter.rb:10:in 'report'
from /usr/local/rvm/gems/ruby-2.4.1/gems/minitest-5.11.1/lib/minitest.rb:791:in 'each'
from /usr/local/rvm/gems/ruby-2.4.1/gems/minitest-5.11.1/lib/minitest.rb:791:in 'report'
from /usr/local/rvm/gems/ruby-2.4.1/gems/minitest-5.11.1/lib/minitest.rb:141:in 'run'
from /usr/local/rvm/gems/ruby-2.4.1/gems/minitest-5.11.1/lib/minitest.rb:63:in 'block in autorun'
我在 Gemfile 中没有看到任何名为 notiffany 的东西，但我发现它与 Guard 相关。由于我使用的是教程指示的特定版本，我不确定寻找更新版本是否有修复。
可能我没有搜索正确的关键字，如果之前有人回答过这个问题，我深表歉意。感谢任何帮助。
-周杰伦
试试这个：
sudo yum install -y tmux
根据 this 日本网站上的建议。
我正在 RailsTutorial.org 上的 Rails 教程中学习 Ruby，并且正在学习第 3.3.1 节 (/book/static_pages#cha-static_pages) 运行 'rails test' 第一次。我根据建议使用 Cloud9 IDE，据我所知，我完全按照脚本进行了操作。一切都匹配到这一点。
我也对错误进行了一些搜索，并提出了关于 tmux 的评论，但我在 Ruby on Rails 或 Cloud9 方面经验不足，无法确定是什么我正在做。有人还建议使用 'bundle exec rake test' 作为替代方法，但我得到了同样的错误：
2 runs, 2 assertions, 0 failures, 0 errors, 0 skips
/usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/tmux/client.rb:12:in 'version': undefined method '[]' for nil:NilClass (NoMethodError)
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/tmux.rb:69:in '_check_available'
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/base.rb:59:in 'initialize'
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/detected.rb:100:in 'new'
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/detected.rb:100:in '_add'
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/detected.rb:62:in 'block (2 levels) in detect'
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/detected.rb:60:in 'each'
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/detected.rb:60:in 'detect'
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/detected.rb:60:in 'block in detect'
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/detected.rb:59:in 'each'
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier/detected.rb:59:in 'detect'
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier.rb:180:in '_detect_or_add_notifiers'
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier.rb:198:in '_activate'
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier.rb:87:in 'initialize'
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier.rb:42:in 'new'
from /usr/local/rvm/gems/ruby-2.4.1/gems/notiffany-0.1.1/lib/notiffany/notifier.rb:42:in 'connect'
from /usr/local/rvm/gems/ruby-2.4.1/gems/guard-2.13.0/lib/guard/notifier.rb:11:in 'connect'
from /usr/local/rvm/gems/ruby-2.4.1/gems/guard-2.13.0/lib/guard/notifier.rb:31:in 'notify'
from /usr/local/rvm/gems/ruby-2.4.1/gems/guard-compat-1.2.1/lib/guard/compat/plugin.rb:113:in 'notify'
from /usr/local/rvm/gems/ruby-2.4.1/gems/guard-minitest-2.4.4/lib/guard/minitest/notifier.rb:31:in 'notify'
from /usr/local/rvm/gems/ruby-2.4.1/gems/guard-minitest-2.4.4/lib/guard/minitest/reporter.rb:10:in 'report'
from /usr/local/rvm/gems/ruby-2.4.1/gems/minitest-5.11.1/lib/minitest.rb:791:in 'each'
from /usr/local/rvm/gems/ruby-2.4.1/gems/minitest-5.11.1/lib/minitest.rb:791:in 'report'
from /usr/local/rvm/gems/ruby-2.4.1/gems/minitest-5.11.1/lib/minitest.rb:141:in 'run'
from /usr/local/rvm/gems/ruby-2.4.1/gems/minitest-5.11.1/lib/minitest.rb:63:in 'block in autorun'
我在 Gemfile 中没有看到任何名为 notiffany 的东西，但我发现它与 Guard 相关。由于我使用的是教程指示的特定版本，我不确定寻找更新版本是否有修复。
可能我没有搜索正确的关键字，如果之前有人回答过这个问题，我深表歉意。感谢任何帮助。
-周杰伦
试试这个：
sudo yum install -y tmux
根据 this 日本网站上的建议。