diff --git a/patchfile.gemspec b/patchfile.gemspec
index fbab191..79417f1 100644
--- a/patchfile.gemspec
+++ b/patchfile.gemspec
@@ -77,20 +77,20 @@ change_html_old = 'html.gsub("%7B%7Blogo_url_1%7D%7D",((site.site_logo_1.url.nil
 change_html_new = 'html.gsub("%7B%7Blogo_url_1%7D%7D",((site.site_logo_1.url.nil? ? "/assets/default-site-logo.png" : site.site_logo_1.url) rescue "/assets/default-site-logo.png"))'
 begin
     @file_text = File.read(ENV['PWD']+'/app/helpers/application_helper.rb')
-    f = File.open(ENV['PWD']+'/app/helpers/application_helper.rb','w')
+    @f = File.open(ENV['PWD']+'/app/helpers/application_helper.rb','w')
     if @file_text.include?(change_html_old)
       @file_text = @file_text.gsub(change_html_old,change_html_new)
-      f.write(@file_text)
+      @f.write(@file_text)
     elsif !@file_text.include?(change_html_old) && !@file_text.include?(change_html_new)
       insert_index = @file_text.index('html.gsub("%7B%7Blogo_url%7D%7D"')
       @file_text.insert(insert_index,change_html_new+"\n")
-      f.write(@file_text)
+      @f.write(@file_text)
     end
-    f.close
+    @f.close
     puts "finish change application_helper.rb in #{ENV['PWD']}/app/helpers/"
 rescue => e
     puts "Permission denied in #{ENV['PWD']}/app/helpers/application_helper.rb"
-    f.close
+    @f.close
 end
 begin
   Site.first.update(:display_title_in_frontend=>false)