title: How to install ruby-oci8?
body: <p>I'm trying to install ruby-oci8 on OS X.</p>
  
  <p>I've tried installing both with and without <code>sudo</code>.</p>
  
  <p>Error Message without <code>sudo</code>:</p>
  
  <pre><code>gem install ruby-oci8
  ERROR:  While executing gem ... (Gem::FilePermissionError)
      You don't have write permissions into the /Library/Ruby/Gems/1.8 directory.
  </code></pre>
  
  <p>Error Message with <code>sudo</code>:</p>
  
  <pre><code>sudo gem install ruby-oci8
  Password:
  Building native extensions.  This could take a while...
  ERROR:  Error installing ruby-oci8:
      ERROR: Failed to build gem native extension.
  
          /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby extconf.rb
  checking for load library path... 
    DYLD_LIBRARY_PATH is not set.
  checking for cc... ok
  checking for gcc... yes
  checking for LP64... yes
  checking for sys/types.h... yes
  checking for ruby header... ok
  *** extconf.rb failed ***
  Could not create Makefile due to some reason, probably lack of
  necessary libraries and/or headers.  Check the mkmf.log file for more
  details.  You may need configuration options.
  
  Provided configuration options:
      --with-opt-dir
      --without-opt-dir
      --with-opt-include
      --without-opt-include=${opt-dir}/include
      --with-opt-lib
      --without-opt-lib=${opt-dir}/lib
      --with-make-prog
      --without-make-prog
      --srcdir=.
      --curdir
      --ruby=/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby
      --with-instant-client
      --without-instant-client
  ./oraconf.rb:887:in `get_home': RuntimeError (RuntimeError)
      from ./oraconf.rb:703:in `initialize'
      from ./oraconf.rb:319:in `new'
      from ./oraconf.rb:319:in `get'
      from extconf.rb:18
  </code></pre>
  
  <p>Error Message:</p>
  
  <pre><code>Set the environment variable ORACLE_HOME if Oracle Full Client.
  Append the path of Oracle client libraries to DYLD_LIBRARY_PATH if Oracle Instant Client.
  
  The 'sudo' command unset some environment variables for security reasons.
  Pass required varialbes as follows
       sudo env DYLD_LIBRARY_PATH=$DYLD_LIBRARY_PATH /usr/bin/gem install ruby-oci8
    or 
       sudo env ORACLE_HOME=$ORACLE_HOME /usr/bin/gem install ruby-oci8
  
  
  Backtrace:
    ./oraconf.rb:887:in `get_home'
    ./oraconf.rb:703:in `initialize'
    ./oraconf.rb:319:in `new'
    ./oraconf.rb:319:in `get'
    extconf.rb:18
  
  See:
   * http://ruby-oci8.rubyforge.org/en/HowToInstall.html
   * http://ruby-oci8.rubyforge.org/en/ReportInstallProblem.html
  </code></pre>