Use Launchy for cross platform site:preview. Thx @ixti.

Rakefile

@@ -118,12 +118,14 @@ end
 namespace :site do
   desc "Generate and view the site locally"
   task :preview do
+    require "launchy"
+
     # Yep, it's a hack! Wait a few seconds for the Jekyll site to generate and
     # then open it in a browser. Someday we can do better than this, I hope.
     Thread.new do
       sleep 4
       puts "Opening in browser..."
-      sh "open http://localhost:4000"
+      Launchy.open("http://localhost:4000")
     end
 
     # Generate the site in server mode.

jekyll.gemspec

@@ -39,6 +39,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency('RedCloth', "~> 4.2")
   s.add_development_dependency('rdiscount', "~> 1.6")
   s.add_development_dependency('redcarpet', "~> 2.1.1")
+  s.add_development_dependency('launchy', "~> 2.1.2")
   
   # = MANIFEST =
   s.files = %w[