How to correctly compose a regular expression for a redirect?

Question

Apache HTTP Server

The URL contains (can start, end or stand in the middle) 5dddd where each d is a digit from 0 to 9
How to write a rule so that such a URL is redirected to a URL like site.ru/?p=5dddd

Answer 1

.*([0-9]{5}).* from zero to nine 5 times any snala and any from the end, in brackets what will be in $1
site.ru/\?p=$1 - substitute what is in brackets

RewriteRule ^.*([0-9]{5}).*$ http://site.ru/\?p=$1 [L,R=301]