How to insert a recent search pattern to use for search-and-replace in vim?

Question

I've entered some search pattern in vim using / command. Now, I want to replace those occurrences I've found with something else.

How do I easily insert the recently used search pattern into the :%s/ command?

The history (accessible via ↑ and ↓ keys) is separate for search and replace, hence my problem.

Answer 1

Pressing CtrlR+/ will insert the last search pattern into the current command line.

:%s/<C-R>//foo/

Answer 2

You can simply omit the search pattern:

:%s//foo