- preg_replace: documentation ( source)
<?php
$email = <<<TEXT
Dear Some Name,
here is your password
...or click the link to login... someurl.com?action=Log%20In&username=someuser@test.com&…
Your log in details are:
Username: your full email address (where this email was received)
Password: yYng6Ytzh Some more bla bla Kind Regards, Admin
TEXT;
echo preg_replace('~Password: \K\S+~', '[redacted]', $email);