rails的命令不再有效

Question

一般来说，我是Rails和编程的新手。我按照YouTube上的一个教程构建了一个应用程序。我完成了所有的工作，然后开始摆弄Ruby和Rails的版本。也许是个错误..。不管怎样，我再也不能让Rails S命令工作了。下面粘贴的是我得到的错误。我欢迎您的任何建议。

/home/tom/apps/BookReview/config/environments/development.rb:3:in @linux：~/ /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/railtie.rb:216:in /BookReview$ rails s =>启动Puma => Rails 5.2.0应用程序在开发中启动=>运行rails server -h以获取更多启动选项退出/home/tom/apps/BookReview/config/environments/development.rb:3:in block in <top (required)>': uninitialized constant Paperclip (NameError) from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/railtie.rb:216:ininstance_eval‘from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/railtie.rb:216:in configure' from /home/tom/apps/BookReview/config/environments/development.rb:1:in’从/ /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/engine.rb:602:in /tom/中从/home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/engine.rb:601:in block (2 levels) in <class:Engine>' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/engine.rb:601:inblock in <class:Engine>' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/initializable.rb:32:ininstance_exec中获取每个‘block (2 levels) in <class:Engine>' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/engine.rb:601:in’。从/ rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/initializable.rb:32:in /tom/.rbenv/run' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/initializable.rb:61:in/2.3中的run_initializers中的/home/tom/.rbenv/versions/2.3.1/lib/ruby/2.3.0/tsort.rb:228:in block in tsort_each' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/2.3.0/tsort.rb:350:in块(2级)中的each_strongly_connected_component中的rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/initializable.rb:32:in版本块。1/lib/ruby/2.3.0/tsort.rb:422:in block (2 levels) in each_strongly_connected_component_from' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/2.3.0/tsort.rb:431:ineach_strongly_connected_component_from‘from /home/tom/.rbenv/versions/2.3.1/lib/ruby/2.3.0/tsort.rb:421:in /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/initializable.rb：block in each_strongly_connected_component_from' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/initializable.rb:50:ineach’50:在从/ /home/tom/.rbenv/versions/2.3.1/lib/ruby/2.3.0/tsort.rb:415:in /tom/.rbenv/versions/2.3.1/lib/each_strongly_connected_component/2进行的tsort_each_child' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/2.3.0/tsort.rb:415:in调用中，‘from /home/tom/.rbenv/versions/2.3.1/lib/ruby/2.3.0/tsort.rb:415:in each_strongly_connected_component_from' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/2.3.0/tsort.rb:349:inblock in each_strongly_connected_component’from homeeach' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/2.3.0/tsort.rb:347:in调用‘。3.0/tsort.rb:347:in /home/tom/.rbenv/versions/2.3.1/lib/ruby/2.3.0/tsort.rb:205:in tsort_each‘from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/application.rb:361:in run_initializers’from /home/tom/.rbenv/versions/2.3.1/lib/ruby/2.3.0/tsort.rb:205:in initialize!' from /home/tom/apps/BookReview/config/environment.rb:5:in‘from config.ru:3:在来自/home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rack-2.0.5/lib的‘from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rack-2.0.5/lib/rack/builder.rb:55:in instance_eval' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rack-2.0.5/lib/rack/builder.rb:55:ininitialize’的require_relative' from config.ru:3:in块中/rack/builder.rb:49:in eval' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rack-2.0.5/lib/rack/builder.rb:49:innew_from_string‘from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rack-2.0.5/lib/rack/builder.rb:40:in parse_file' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rack-2.0.5/lib/rack/server.rb:319:inbuild_app_and_options_from_config’from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rack-2.0.5/lib/rack/server.rb:219:来自/home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0的app' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/commands/server/server_command.rb:27:in应用程序‘from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rack-2.0.5/lib/rack/server.rb:354:in wrapped_app' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/commands/server/server_command.rb:89:inlog_to_stdout’从/home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/thor执行‘from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/commands/server/server_command.rb:142:in start' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/commands/server/server_command.rb:147:in perform’中的/home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/thor start' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/commands/server/server_command.rb:147:inblock-0.20.0/lib/thor/command.rb d.rb:27:in run' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/thor-0.20.0/lib/thor/invocation.rb:126:ininvoke_command‘from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/thor-0.20.0/lib/thor.rb:387:in dispatch' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/command/base.rb:65:inperform’from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/command.rb:46:in BookReview‘from /home/tom/invoke' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/commands.rb:18:in/bin/require' from /home/tom/apps/BookReview/bin/rails:9:in：9:in rails’from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/ load' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/spring-2.0.2/lib/spring/client/rails.rb:28:incall‘从/home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/spring-‘from 2.3.0/gems/spring-2.0.2/lib/spring/client/command.rb:7:in <top (required)>' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/spring-2.0.2/lib/spring/binstub.rb:31:inload’运行/home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/spring-call' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/spring-2.0.2/lib/spring/client.rb:30:in2.0.2/lib/spring/binstub.rb:31:in rails需要‘from /home/tom/.rbenv/versions/2.3.1/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:68:in require' from /home/tom/apps/BookReview/bin/spring:15:in’from bin/<top (required)>' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:68:in：3:in load' from bin/rails:3:in‘

Answer 1

在Gemfile中包括回形针宝石，如果它还没有添加的话。

gem "paperclip", git: "git://github.com/thoughtbot/paperclip.git"

之后运行bundle install