/*
Plugin Name: Substitute Displayname
Version: 0.1
Description: Substitutes a default Display name for new registrants and existing users.
Author: Author name
*/
?>
/* Version check */
global $wp_version;
$exit_msg='Substitute Author requires WordPress 2.5 or newer. Please update!';
if (version_compare($wp_version,"2.5","<")) {
exit ($exit_msg);
}
function sd_new_login_filter ($login) {
/* Don't do anything to login, just see if already in database.*/
global $wpdb, $sd_is_new_login;
$id = $wpdb->get_var("SELECT ID FROM $wpdb->users WHERE user_login = '$login'");
$sd_is_new_login = (isset($id)) ? false : true;
return $login;
}
function sd_substitute_displayname_filter ($display_name) {
global $sd_is_new_login;
if ($sd_is_new_login){
$first_letter = substr($_POST['last_name'], 0, 1);
$display_name = $_POST['first_name']." ".$first_letter;
}
return $display_name;
}
add_filter('pre_user_login', 'sd_new_login_filter');
add_filter('pre_user_display_name', 'sd_substitute_displayname_filter');
add_action ('admin_head','make_display_name_f_name_last_name');
function make_display_name_f_name_last_name(){
$users = get_users(array('fields'=>'all'));
foreach($users as $user){
$user = get_userdata($user->ID);
$firstletter = substr($user->last_name, 0, 1);
$display_name = $user->first_name . " " . $firstletter;
if($display_name!=' ') wp_update_user( array ('ID' => $user->ID, 'display_name' => $display_name) );
else wp_update_user( array ('ID' => $user->ID, 'display_name' => $user->display_login) );
if($user->display_name == '')
wp_update_user( array ('ID' => $user->ID, 'display_name' => $user->display_login) );
}
}
?>
Done with the help of following threads:
1. http://stackoverflow.com/questions/9326315/wordpress-change-default-display-name-publicy-as-for-all-existing-users
2. http://wordpress.org/support/topic/change-default-display-name-1
