--- a/installer.rb
+++ b/installer.rb
@@ -596,7 +596,7 @@
 				rest = nil
 				File.open(filename, 'rb') do |f|
 					shebang = f.readline
-					if shebang =~ /ruby/
+					if shebang =~ /^#!.*ruby/
 						puts "Updating #{filename}..."
 						rest = f.read
 					end