title: Did I install Ruby 1.9.3 correctly on RHEL?
body: <p>Before you say <code>yum -y install ruby193</code>...  I did that.</p>
  
  <p>Please note that I am not a Ruby developer, but need this program as part of another developer's work via web services. (He is not available.) Any help would be greatly appreciated.</p>
  
  <p>I attempted to install a library per instructions and got:</p>
  
  <pre><code>[root@ctbroker console]# gem install json -v '1.8.0'
  Building native extensions.  This could take a while...
  ERROR:  Error installing json:
  ERROR: Failed to build gem native extension.  /opt/rh/ruby193/root/usr/bin/ruby extconf.rb
  mkmf.rb can't find header files for ruby at /opt/rh/ruby193/root/usr/share/include/ruby.h
  Gem files will remain installed in /opt/rh/ruby193/root/usr/local/share/gems/gems/json-1.8.0 for inspection.
  Results logged to /opt/rh/ruby193/root/usr/local/share/gems/gems/json-1.8.0/ext/json/ext/generator/gem_make.out
  </code></pre>
  
  <p>I noticed that <code>ruby.h</code> is only on the machine at <code>/usr/lib64/ruby/1.8/x86_64-linux/ruby.h</code>.</p>
  
  <p>What am I missing?</p>