diff --git a/tool/rbinstall.rb b/tool/rbinstall.rb
index 490f5f3281..854fa07e14 100755
--- a/tool/rbinstall.rb
+++ b/tool/rbinstall.rb
@@ -693,7 +693,16 @@ module RbInstall
     def shebang(bin_file_name)
       path = File.join(gem_dir, spec.bindir, bin_file_name)
       first_line = File.open(path, "rb") {|file| file.gets}
-      $script_installer.prolog(first_line)
+      $script_installer.prolog(first_line).chomp
+    end
+
+    def app_script_text(bin_file_name)
+      # move shell script part after comments generated by RubyGems.
+      super.sub(/\A
+        (\#!\/bin\/sh\n\#.*-\*-\s*ruby\s*-\*-.*\n)
+        ((?:.*\n)*?\#!.*ruby.*\n)
+        \#\n
+        ((?:\#.*\n)+)/x, '\1\3\2')
     end
 
     def check_executable_overwrite(filename)