How to automatically create a custom field when a post is published?

Question

I'm trying to add custom fields on post publish with this code which I added to my functions.php :

add_action('publish_page', 'add_custom_field_automatically');
add_action('publish_post'. 'add_custom_field_automatically');
function add_custom_field_automatically($post_ID) {
    global $wpdb;
    if(!wp_is_post_revision($post_ID)) {
        add_post_meta($post_ID, 'FIELD_NAME', 'CUSTOM VALUE', true);
    }
}

This code should work but it doesn't ? I updated field and custom value but custom fields are never created.Why ?

Answer 1

add_action('publish_post'. 'add_custom_field_automatically');

You have a period in the second add_action. This should be a comma :)