我尝试在 Mac OS X 上安装 Rails。我已经安装了ruby。
$ ruby -v
ruby 2.0.0p247 (2013-06-27 revision 41674) [x86_64-darwin11.4.2]
我检查 Rails 是否已安装：
$ rails -v
Rails is not currently installed on this system. To get the latest version, simply type:
$ sudo gem install rails
You can then rerun your "rails" command.
然后我运行：
$ sudo gem install rails
Password:
Successfully installed rails-4.0.0
Parsing documentation for rails-4.0.0
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/belongs_to.png, skipping
unable to convert "\xF4" from ASCII-8BIT to UTF-8 for guides/assets/images/book_icon.gif, skipping
unable to convert "\x91" from ASCII-8BIT to UTF-8 for guides/assets/images/bullet.gif, skipping
unable to convert "\xF5" from ASCII-8BIT to UTF-8 for guides/assets/images/chapters_icon.gif, skipping
unable to convert "\xF5" from ASCII-8BIT to UTF-8 for guides/assets/images/check_bullet.gif, skipping
unable to convert "\xF4" from ASCII-8BIT to UTF-8 for guides/assets/images/credits_pic_blank.gif, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/csrf.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/edge_badge.png, skipping
unable to convert "\x9E" from ASCII-8BIT to UTF-8 for guides/assets/images/favicon.ico, skipping
unable to convert "\x80" from ASCII-8BIT to UTF-8 for guides/assets/images/feature_tile.gif, skipping
unable to convert "\x80" from ASCII-8BIT to UTF-8 for guides/assets/images/footer_tile.gif, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/fxn.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/getting_started/challenge.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/getting_started/confirm_dialog.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/getting_started/forbidden_attributes_for_new_post.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/getting_started/form_with_errors.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/getting_started/index_action_with_edit_link.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/getting_started/new_post.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/getting_started/post_with_comments.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/getting_started/rails_welcome.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/getting_started/routing_error_no_controller.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/getting_started/routing_error_no_route_matches.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/getting_started/show_action_for_posts.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/getting_started/template_is_missing_posts_new.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/getting_started/undefined_method_post_path.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/getting_started/unknown_action_create_for_posts.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/getting_started/unknown_action_new_for_posts.png, skipping
unable to convert "\xF0" from ASCII-8BIT to UTF-8 for guides/assets/images/grey_bullet.gif, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/habtm.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/has_many.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/has_many_through.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/has_one.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/has_one_through.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/header_backdrop.png, skipping
unable to convert "\x80" from ASCII-8BIT to UTF-8 for guides/assets/images/header_tile.gif, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/i18n/demo_html_safe.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/i18n/demo_localized_pirate.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/i18n/demo_translated_en.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/i18n/demo_translated_pirate.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/i18n/demo_translation_missing.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/i18n/demo_untranslated.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/icons/callouts/1.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/icons/callouts/10.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/icons/callouts/11.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/icons/callouts/12.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/icons/callouts/13.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/icons/callouts/14.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/icons/callouts/15.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/icons/callouts/2.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/icons/callouts/3.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/icons/callouts/4.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/icons/callouts/5.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/icons/callouts/6.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/icons/callouts/7.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/icons/callouts/8.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/icons/callouts/9.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/icons/caution.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/icons/example.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/icons/home.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/icons/important.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/icons/next.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/icons/note.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/icons/prev.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/icons/tip.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/icons/up.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/icons/warning.png, skipping
unable to convert "\xFF" from ASCII-8BIT to UTF-8 for guides/assets/images/jaimeiniesta.jpg, skipping
unable to convert "\xF5" from ASCII-8BIT to UTF-8 for guides/assets/images/nav_arrow.gif, skipping
unable to convert "\xFF" from ASCII-8BIT to UTF-8 for guides/assets/images/oscardelben.jpg, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/polymorphic.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/radar.png, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/rails4_features.png, skipping
unable to convert "\xFF" from ASCII-8BIT to UTF-8 for guides/assets/images/rails_guides_kindle_cover.jpg, skipping
unable to convert "\xEC" from ASCII-8BIT to UTF-8 for guides/assets/images/rails_guides_logo.gif, skipping
unable to convert "\x8C" from ASCII-8BIT to UTF-8 for guides/assets/images/rails_logo_remix.gif, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/session_fixation.png, skipping
unable to convert "\x80" from ASCII-8BIT to UTF-8 for guides/assets/images/tab_grey.gif, skipping
unable to convert "\x80" from ASCII-8BIT to UTF-8 for guides/assets/images/tab_info.gif, skipping
unable to convert "\x80" from ASCII-8BIT to UTF-8 for guides/assets/images/tab_note.gif, skipping
unable to convert "\x80" from ASCII-8BIT to UTF-8 for guides/assets/images/tab_red.gif, skipping
unable to convert "\x80" from ASCII-8BIT to UTF-8 for guides/assets/images/tab_yellow.gif, skipping
unable to convert "\x89" from ASCII-8BIT to UTF-8 for guides/assets/images/tab_yellow.png, skipping
unable to convert "\xFF" from ASCII-8BIT to UTF-8 for guides/assets/images/vijaydev.jpg, skipping
1 gem installed
然后我重新运行rails -v：
$ rails -v
Rails is not currently installed on this system. To get the latest version, simply type:
$ sudo gem install rails
You can then rerun your "rails" command.
结果相同。问题：我错过了什么？
附加信息rvm：
$ rvm -v
rvm 1.21.10 (stable) by Wayne E. Seguin <[email protected]>, Michal Papis <[email protected]> [https://rvm.io/]
注意：我的 Mac OS X 是 10.7.5，我的账户有管理员权限。当前目录是~（主目录）
更新：以下是根据评论得出的输出：
$ gem -v
2.0.5
$ which gem
/Users/MyUserName/.rvm/rubies/ruby-2.0.0-p247/bin/gem
我下一步该做什么？
答案1
正如我在评论中提到的，首先确保ruby和gem指向 RVM 安装的版本，而不是 中的版本/usr/bin。
还要确保您使用新的 Ruby 作为默认设置：
rvm --default use 2.0.0-p247
gemset创建用于此 Ruby 版本的Gemset（名为）：
rvm use 2.0.0-p247@gemset --create --default
然后将 Rails 安装到该 Gemset：
gem install rails
这应该足以使用新rails版本。如果不行，请尝试重新启动 shell。
答案2
gem install rails --no-ri --no-rdoc我得到以下信息后尝试：
Successfully installed rails-4.0.0
1 gem installed
我打开了一个新的终端窗口并尝试rails --version...Rails 4.0.0。也许魔法就在于打开一个新窗口。