htaccess redirect if URL contains a certain string

Question

How would I write a .htaccess redirect rule if the URL contains a certain word?

e.g. if it contains foobar then redirect to index.php

Answer 1

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^/foobar/i$ index.php [NE,L]