$re = '/(vendor\/devowl-wp\/[^\/]+\/languages\/frontend\/json\/)devowl-wp-/m';
$str = '/var/www/html/wp-content/plugins/real-category-library/vendor/devowl-wp/real-product-manager-wp-client/languages/frontend/json/devowl-wp-real-product-manager-wp-client-de_DE_formal-vendor-devowl-wp-real-product-manager-wp-client.json';
$subst = "$1";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php