Fix a problem with incorrect content_type detected with 'file' command for an empty file on Mac

lib/paperclip/io_adapters/file_adapter.rb

@@ -69,7 +69,7 @@ module Paperclip
     def type_from_file_command
       # On BSDs, `file` doesn't give a result code of 1 if the file doesn't exist.
       type = (self.original_filename.match(/\.(\w+)$/)[1] rescue "octet-stream").downcase
-      mime_type = (Paperclip.run("file", "-b --mime :file", :file => self.path).split(/[:;]\s+/)[0] rescue "application/x-#{type}")
+      mime_type = (Paperclip.run("file", "-b --mime :file", :file => self.path).split(/[:;\s]+/)[0] rescue "application/x-#{type}")
       mime_type = "application/x-#{type}" if mime_type.match(/\(.*?\)/)
       mime_type
     end

test/file_adapter_test.rb

@@ -20,6 +20,13 @@ class FileAdapterTest < Test::Unit::TestCase
       assert_equal "image/png", @subject.content_type
     end
 
+    should "provide correct mime-type for empty file" do
+      @subject = Paperclip.io_adapters.for(Tempfile.new("file_adapter_test"))
+
+      # Content type contained '\n' at the end, for an empty file, on my Mac
+      assert_equal "application/x-empty", @subject.content_type
+    end
+
     should "get the file's size" do
       assert_equal 4456, @subject.size
     end