title: activesupport requires Ruby version >= 1.9.3 while running ruby 2
body: <p>I have Ruby v2 installed:</p>
  
  <pre><code>$ ruby --version
  ruby 2.1.2p95 (2014-05-08 revision 45877) [x86_64-darwin11.0]
  </code></pre>
  
  <p>but I get this error on multiple gems when I run:</p>
  
  <pre><code>$ sudo gem update
  </code></pre>
  
  <p>What's the problem and how do I fix it?</p>
  
  <h2>EDIT 1:</h2>
  
  <pre><code>$ gem update
  Updating installed gems
  Updating actionmailer
  Fetching: activesupport-4.1.8.gem (100%)
  ERROR:  While executing gem ... (Gem::FilePermissionError)
      You don't have write permissions for the /Library/Ruby/Gems/1.8 directory.
  </code></pre>
  
  <h2>EDIT 2:</h2>
  
  <pre><code>$ gem env
  RubyGems Environment:
  - RUBYGEMS VERSION: 2.4.5
  - RUBY VERSION: 1.8.7 (2012-02-08 patchlevel 358) [universal-darwin11.0]
  - INSTALLATION DIRECTORY: /Library/Ruby/Gems/1.8
  - RUBY EXECUTABLE: /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby
  - GEM PATHS:
      - /Library/Ruby/Gems/1.8
      - /Users/user/.gem/ruby/1.8
      - /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8
  
  $ rvm info
  -bash: rvm: command not found
  </code></pre>