diff --git a/lib/guard/rails/runner.rb b/lib/guard/rails/runner.rb
index 630c898..27bcc78 100644
--- a/lib/guard/rails/runner.rb
+++ b/lib/guard/rails/runner.rb
@@ -74,19 +74,18 @@ module Guard
     end
 
     def unmanaged_pid
-      if RbConfig::CONFIG['host_os'] =~ /darwin/
-        %x{lsof -P}.each_line { |line|
-          if line["*:#{options[:port]} "]
-            return line.split("\s")[1]
-          end
-        }
-      elsif RbConfig::CONFIG['host_os'] =~ /linux/
-        %x{lsof -i :#{options[:port]}}.each_line { |line|
-          if line["*:#{options[:port]} "]
-            return line.split("\s")[1]
-          end
-        }
-      end
+      pid_command = 
+        case RbConfig::CONFIG['host_os'] 
+        when /darwin/i
+          'lsof -P'
+        when /linux/i 
+          "lsof -i :#{options[:port]}"
+        end
+      %x{#{pid_command}}.each_line { |line|
+        if line["*:#{options[:port]} "]
+          return line.split("\s")[1]
+        end
+      }
       nil
     end
   end