OS X 10.8, unsigned application: reset open confirmation

Question

When I try to open an unsigned application by double clicking it in OS X 10.8's Finder, it rejects it. When I right-click the application and select Open, it shows a confirmation dialog. When confirming this with "Open", I can open the application the next time.

How I can reset this behavior, so OS X 10.8 will again reject to double-click this application?

I need this to test our application in a default environment without having to reinstall a backup.

Answer 1

You can add it using xattr from a command prompt, for example to indicate it was downloaded by Safari and have it quarantined as such, just do;

xattr -w com.apple.quarantine "0000;4b3a40d0;Safari;|com.apple.Safari" <path to file>;