我在我的Ubuntu主目录中，尝试使用rails new创建一个新的rails应用程序，但是我收到了这个错误：
i18n gem不可用。请将其添加到gem文件中，然后运行捆绑安装
我运行的任何rails命令都会给出这个错误。我真的很困惑，因为我不在应用程序中。我只是在我的主目录中。没有gemfile。我尝试用gem install 'i18n'将"i18n"安装到我的主目录中，它工作正常，但我仍然得到这个错误。
我以前在主目录中使用rails命令时从来没有遇到过任何问题。当我将cd插入到我的各个应用程序中时，与rails相关的所有命令都正常工作。这是怎么回事？

• • 还有**，我现在在所有现有的rails应用程序中都遇到了同样的错误。是rails突然变得依赖于那个gem了吗？还是删除了我主目录中的gem，使得它在我的应用程序中不可用了？

更新

我尝试了gem cleanup rails并重新安装，但没有任何变化。以下是结果：

$ gem cleanup rails
  Cleaning up installed gems...
  Attempting to uninstall rails-4.0.10
  Successfully uninstalled rails-4.0.10
  Attempting to uninstall rails-4.2.1
  Successfully uninstalled rails-4.2.1
  Attempting to uninstall rails-4.2.4
  Successfully uninstalled rails-4.2.4
  Attempting to uninstall rails-5.0.1
  Successfully uninstalled rails-5.0.1
  Attempting to uninstall rails-5.0.2
  Successfully uninstalled rails-5.0.2
  Attempting to uninstall rails-5.0.3
  Successfully uninstalled rails-5.0.3
  Attempting to uninstall rails-5.0.4
  Successfully uninstalled rails-5.0.4
  Clean Up Complete
$ gem install rails -v 5.0.1
  Fetching: rails-5.0.1.gem (100%)
  Successfully installed rails-5.0.1
  Parsing documentation for rails-5.0.1
  Installing ri documentation for rails-5.0.1
  Done installing documentation for rails after 1 seconds
  1 gem installed
$ rails -v
  The i18n gem is not available. Please add it to your Gemfile and run bundle install

更新2

我之前手动安装了i18n，我想这可能是问题所在，所以我卸载了rails和i18n，然后重新安装了rails。

$ gem uninstall rails --all

You have requested to uninstall the gem:
    rails-5.0.1

browser-2.3.0 depends on rails (>= 0, development)
browser-1.1.0 depends on rails (>= 0, development)
browser-0.9.1 depends on rails (>= 0, development)
carrierwave-1.2.1 depends on rails (>= 4.0.0, development)
carrierwave-1.0.0 depends on rails (>= 4.0.0, development)
rails_serve_static_assets-0.0.5 depends on rails (>= 3.1, development)
rails_serve_static_assets-0.0.4 depends on rails (>= 3.1, development)
sass-rails-4.0.5 depends on rails (>= 0, development)
sunspot_rails-2.2.7 depends on rails (>= 3)
twitter-typeahead-rails-0.10.5 depends on rails (>= 3.1, development)
yaml_db_improved-1.0.1 depends on rails (>= 0)
If you remove this gem, these dependencies will not be met.
Continue with Uninstall? [yN]  y
Successfully uninstalled rails-5.0.1

  $ gem uninstall i18n --all

You have requested to uninstall the gem:
    i18n-0.9.1

activesupport-5.1.4 depends on i18n (~> 0.7)
activesupport-5.0.5 depends on i18n (~> 0.7)
activesupport-5.0.4 depends on i18n (~> 0.7)
activesupport-5.0.3 depends on i18n (~> 0.7)
activesupport-5.0.2 depends on i18n (~> 0.7)
activesupport-5.0.1 depends on i18n (~> 0.7)
activesupport-4.2.4 depends on i18n (~> 0.7)
activesupport-4.2.1 depends on i18n (~> 0.7)
activesupport-4.0.10 depends on i18n (>= 0.6.9, ~> 0.6)
capistrano-3.8.0 depends on i18n (>= 0)
capistrano-3.7.2 depends on i18n (>= 0)
If you remove this gem, these dependencies will not be met.
Continue with Uninstall? [yN]  y
Successfully uninstalled i18n-0.9.1

  $ gem install rails --version 5.0.1

Fetching: i18n-0.9.1.gem (100%)
Successfully installed i18n-0.9.1
Fetching: rails-5.0.1.gem (100%)
Successfully installed rails-5.0.1
Parsing documentation for i18n-0.9.1
Installing ri documentation for i18n-0.9.1
Parsing documentation for rails-5.0.1
Installing ri documentation for rails-5.0.1
Done installing documentation for i18n, rails after 4 seconds
2 gems installed

  $ rails -v

The i18n gem is not available. Please add it to your Gemfile and run bundle install
/home/user/.rvm/rubies/ruby-2.3.3/lib/ruby/site_ruby/2.3.0/rubygems/specification.rb:2278:in `check_version_conflict': can't activate activesupport-5.1.4, alrea
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