Why I can't install rails with gem install rails -v 4.0.0?

Question

I have installed on GNU/Linux:

rvm 1.23.16 (stable) by Wayne E. Seguin , Michal Papis [https://rvm.io/]
ruby 2.0.0p247 (2013-06-27 revision 41674) [x86_64-darwin12.4.0]

I apparently have all gems in my system, but when I run the command: gem install rails -v 4.0.0 it states that one gem was installed. But Rails isn't installed yet.

When I use gem install rails -v 4.0.0 or gem install rails --version=4.0 occurs that:

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

How I can install Rails 4.0.0 using RVM?

Answer 1

These error messages are being created while the Rails documentation is being installed on your machine. I found two Rails issues discussing this: #9590 and #11814.

This is ultimately an issue with rdoc and ruby 2.0 that was fixed but isn't in a released version of rdoc yet.

There are a few ways to get around this, I'm listing them in the order I would probably try them:

1. Don't install the documentation with the rails gem; instead of running gem install rails do gem install rails --no-rdoc --no-ri. I hardly ever use built in documentation anyway, so I actually have gem: --no-ri --no-rdoc in my ~/.gemrc file so that documentation is never installed for any gem.

2. Install rails without documentation as in #1, but then build the documentation by hand using rdoc and the --exclude='.dat' flag, like rdoc --exclude='.dat' activesupport/lib to build the activesupport docs, as recommended in this comment.

3. Install rdoc from github at a commit that is later than ceb81dd11. Using bundler's git or github options in your Gemfile make this easy, but there must be other reasons that a new version hasn't been released yet, so there might be bugs.