diff --git a/Library/Homebrew/keg_fix_install_names.rb b/Library/Homebrew/keg_fix_install_names.rb
index f490a9c790..7356efcd20 100644
--- a/Library/Homebrew/keg_fix_install_names.rb
+++ b/Library/Homebrew/keg_fix_install_names.rb
@@ -42,10 +42,13 @@ class Keg
 
     files.group_by { |f| f.stat.ino }.each_value do |first, *rest|
       s = first.open("rb", &:read)
-      s.gsub!(old_cellar, new_cellar)
-      s.gsub!(old_prefix, new_prefix)
-      first.atomic_write(s)
-      rest.each { |file| FileUtils.ln(first, file, :force => true) }
+      changed = s.gsub!(old_cellar, new_cellar)
+      changed = s.gsub!(old_prefix, new_prefix) || changed
+
+      if changed
+        first.atomic_write(s)
+        rest.each { |file| FileUtils.ln(first, file, :force => true) }
+      end
     end
   end