Question

How can use regex to make sure that is only a single slash end the end of an URL or any input string?

$url = 'http://example.com//';
if(!preg_match('/\/$/', $url))
{
    echo 'the url must ends with a \'/\'';
}

This accepts two or more slashes which is not correct.

Answer 1

I think you can do like this:

~(?:[^/]|^)/$~

I have not tested it, the idea is to test if there is not a / before the / at the end of the string (and in this version to allow the start of a string as well, so the "/" string is valid as well.