PHP, regex and double quoted strings are fun...

PHP - finding escaped backslashes

<?php

/* This handy script lets you locate escaped backslashes in the prettiest way. */

$input = $_POST['value'];

$matches = array();
if (preg_match("/\\\\/", $input, $matches)) {
    var_dump($matches);
} else {
    echo "No matching \"\\\\\"'s found.";
}