将 Ubuntu 从 10.04 更新到 14.04 后 Rails 无法正常工作

Question

我在 Ubuntu 10.04 中安装了 Rails。并启动并运行了一些应用程序。但是在将 Ubuntu 更新到 14.04 后，rails 应用程序无法运行。

当我尝试启动我的 Rails 应用程序（作为 $rails 服务器）时，收到以下警告和帮助：

bin/rails:6: warning: already initialized constant APP_PATH
/home/razor/rails_projs/simple_cms/bin/rails:6: warning: previous definition of APP_PATH was here
Usage: rails COMMAND [ARGS]

The most common rails commands are:
 generate    Generate new code (short-cut alias: "g")
 console     Start the Rails console (short-cut alias: "c")
 server      Start the Rails server (short-cut alias: "s")
 dbconsole   Start a console for the database specified in config/database.yml
         (short-cut alias: "db")
 new         Create a new Rails application. "rails new my_app" creates a
         new application called MyApp in "./my_app"

In addition to those, there are:
 application  Generate the Rails application code
 destroy      Undo code generated with "generate" (short-cut alias: "d")
 plugin new   Generates skeleton for developing a Rails plugin
 runner       Run a piece of code in the application environment (short-cut alias: "r")

All commands can be run with -h (or --help) for more information.

Answer 1

This link，帮我解决了这个问题。 我不得不卸载 mysql2 gem 然后重新安装。

我使用的命令

$gem uninstall mysql2
$gem install mysql2

一切都很好，可以启动服务器了。

Answer 2

当我错误地尝试从 app 目录外部并再次从 gem/engine 目录内部运行 rails server 时，我发生了这种情况。你能确认你在你的主应用程序中吗？如果您的应用名称是 simple_cms，看起来您就是。

如果是这样，那么你运行时会得到什么

type rails

和

which rails

奇怪的是，它为您提供了从应用程序中创建应用程序的选项，这是不可能的。你安装了哪个版本的rails？