WP-Mix

Here’s how to filter content in WordPress’ header.php template file using PHP.

Just edit the path to your theme’s header.php file, and modify the str_replace() parameters to match and replace the target content.

<?php // Replace content in WordPress header.php
// @ https://wp-mix.com/replace-content-wordpress-header/

ob_start();
include '/path/to/httpdocs/wp-content/themes/yourtheme/header.php'; // PATH
$data = ob_get_clean();
$data = str_replace('<title>wp-mix.com</title>', '<title>wp-mix.com : more</title>', $data); // REGEX
echo $data; 

?>

In this example we’re using <title>wp-mix.com</title> to find all instances of <title>wp-mix.com : more</title> and replace each with . May be useful for other WordPress theme files as well. Have phun!