title: Upgrading to Ruby 2.0, overwrite executables without prompt
body: <p>When upgrading from ruby 1.9.3 to ruby 2.0 on linux (at least 12.04) you get an unexpected prompt.  </p>
  
  <pre><code>rdoc's executable "rdoc" conflicts with /path/bin/rdoc
  Overwrite the executable? [yN]  
  </code></pre>
  
  <p>It works fine to overwrite it manually but I'm looking for a way that my scripts will auto reply yes without halting.</p>
  
  <p>Just found this issue on <a href="https://github.com/rubygems/rubygems/pull/280">rubygems from a year ago</a>.  I'm using <code>gem install</code> in a script so I think I can somewhat easily add <code>yes | gem install</code></p>
  
  <p>Edit:
  Tried <code>yes | gem install rdoc</code> but it fails with:</p>
  
  <pre><code>ERROR:  Error installing rdoc:
  "rdoc" from rdoc conflicts with /usr/local/rubies/2.0.0-p0/bin/rdoc
  </code></pre>