试图在Windows 7上的Rails（版本4.0.0）上重新安装Ruby（版本2.0.0）

Question

I had Ruby-on-Rails installed, but it was Ruby version 1.9.3. It was installed via the Railsinstaller. Since I am just starting in RoR, I wanted to start with the most updated versions to go through the Ruby on Rails Tutorial. Rails was easy enough to update, but not Ruby itself.

I uninstalled the existing RailsInstaller, deleted the c:\\Railsinstaller directory and downloaded the latest version of RailsInstaller, version 3.0.0-alpha.1.

Upon install it launches a command prompt window that should list the install infor for git, ruby and rails. Instead I got this error:

The system cannot find the path specified.

 Rails Environment Configuration.  
C:/RailsInstaller/scripts/config_check.rb:28:in ``': No such file or directory -  
 rails -v (Errno::ENOENT)  
        from C:/RailsInstaller/scripts/config_check.rb:28:in `run'  
        from C:/RailsInstaller/scripts/config_check.rb:83:in `<main>'  
C:\Sites>

Line 28 is part of this block:

def run(command)
  $stderr.puts "Running #{command}" if Config[:debug]
  %x{#{command}}.chomp
end

and line 83 is this inside of a 'puts' block:

  version:    #{run "rails -v"}

manually running "rails -v"

C:\Sites>rails -v
'rails' is not recognized as an internal or external command,
operable program or batch file.

attempting "ruby rails.rb" ruby: No such file or directory -- rails.rb (LoadError)

attempting to manually install the rails gem

c:\Sites>gem install rails --version 4.0.0  

Fetching: i18n-0.6.4.gem (100%)  
Successfully installed i18n-0.6.4  
Fetching: atomic-1.1.10.gem (100%)  
Temporarily enhancing PATH to include DevKit...  
Building native extensions.  This could take a while...  
The system cannot find the path specified.  
ERROR:  Error installing rails:  
        ERROR: Failed to build gem native extension.  

    C:/RailsInstaller/Ruby2.0.0/bin/ruby.exe extconf.rb  
creating Makefile  


Gem files will remain installed in C:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0  
.0/gems/atomic-1.1.10 for inspection.  
Results logged to C:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/atomic-1.  
1.10/ext/gem_make.out  

The gem_make.out only contains:

C:/RailsInstaller/Ruby2.0.0/bin/ruby.exe extconf.rb  
creating Makefile

I attempted to install Railsinstaller 3.0.0 on a windows xp machine to test, and got the same error after the install, running "rails -v" failed in the same way, but running "gem install rails --version 4.0.0" worked.

Did something persist from the previous install that is preventing the new install from functioning properly?

I think something is still trying to go to the Ruby1.9.3 forlder and/or subfolders and failing, but can't find anything referencing that directory.

Answer 1

After a bunch of additional research and out side help, found this:

You've installed both RubyInstaller and DevKit following the instructions but during gem installation, you receive a message like this:

C:\devkit>gem install rdiscount --platform=ruby
Temporarily enhancing PATH to include DevKit...
Building native extensions.  This could take a while...
ERROR:  Error installing rdiscount:
       ERROR: Failed to build gem native extension.

C:/ruby/bin/ruby.exe extconf.rb
C:/ruby/bin/ruby.exe: No such file or directory -- extconf.rb
(LoadError)

Or sometimes just this:

ERROR:  Error installing rdiscount:
       ERROR: Failed to build gem native extension.

       C:/Ruby187/bin/ruby.exe extconf.rb

This has been reported to our group here and here.

After a long back and forth investigation, we found two possible causes for this issue: COMSPEC environment variable (scenario A) and AutoRun registry setting (scenario B), both described below:

Scenario A

Using a command prompt, invoke the following command:

SET COMSPEC

If in the output you see something different than cmd.exe as value for that variable, then please adjust it to use cmd.exe

Some tools might change your command processor command, which interferes with Ruby invoking child processes.

Change that and try to install the gem again.

Scenario B

If the problem persist, invoke the following commands in the same command prompt:

REG QUERY "HKCU\Software\Microsoft\Command Processor"
REG QUERY "HKLM\Software\Microsoft\Command Processor" /s

Execute each line individually. Once you run it, will see something like this:

HKEY_CURRENT_USER\Software\Microsoft\Command Processor
    CompletionChar    REG_DWORD    0x9
    DefaultColor    REG_DWORD    0x0
    EnableExtensions    REG_DWORD    0x1
    PathCompletionChar    REG_DWORD    0x9

The columns of information are Key, Type and Value. If you see a key named AutoRun, there is a chance this is the culprit of the error you're receiving.

AutoRun interferes with Ruby messing with child process executing and by result, affecting gem installation. Please remove it with the following command:

REG DELETE "HKCU\Software\Microsoft\Command Processor" /v AutoRun

Once you're done, try opening a new command prompt and executing gem installation again.

Scenario B ended up being the culprit and things began working properly once that was completed.

Answer 2

I apologize that this doesn't actually answer your question at hand, but I think it's still useful advice to you:

Consider downloading Virtualbox and installing some Linux (Fedora, Ubuntu) on it and doing your Rails development on that Linux virtual machine. It won't mess with your Windows system at all, but it will be much easier to develop Rails with.

Almost nobody develops Rails on Windows, everyone uses Mac or Linux it seems. And I always read people having problems setting it up on Windows. It just doesn't seem worth the effort to me when you have free tools out there to develop on Linux.

Again, sorry this isn't actually the proper answer to the question. Even once you find the answer to your problem, I'd still recommend you consider this advice. You're likely to have more problems with Rails on Windows.