Error installing Rails

Hi guys

I'm a Rails virgin. I'm pulling my hair out with the install.

So far, I've checked that I've got Ruby & Gems, see below;

Pauls-iMac:~ pauldoran$ ruby --version
ruby 1.8.7 (2012-02-08 patchlevel 358) [universal-darwin12.0]

Pauls-iMac:~ pauldoran$ gem --version

I'm trying to install Rails as follows;

Pauls-iMac:~ pauldoran$ sudo gem install rails

But get the following error message;

ERROR: Error installing rails:
  ERROR: Failed to build gem native extension.

mkmf.rb can't find header files for ruby at

Gem files will remain installed in
/Library/Ruby/Gems/1.8/gems/json-1.7.6 for inspection.
Results logged to

I've read the forum for similar errors but non of the fixes seem to

Any help would be so appreciated.

I advise using rvm to install ruby and rails


First, install rbenv/ruby-build or RVM


Then install ruby 1.9.3

Then install rails

Good luck!