Show the WordPress toolbar by default

functions.php

<?php
/**
 * Show the toolbar by default
 *
 * We only want to set this preference once per user so we save a flag which is
 * checked before modifying their user settings.
 *
 * @author iWeb
 * @link https://goo.gl/z384Uj
 */
function iweb_show_toolbar() {
	if ( in_array( $GLOBALS['pagenow'], array( 'post.php', 'post-new.php' ) ) ) {
		$user_id = get_current_user_id();

		// This is a one time deal, bail if the user has already had their default set
		if ( get_user_meta( $user_id, 'iweb_show_toolbar', true ) ) {
			return;
		}

		set_user_setting( 'hidetb', '1' );
		update_user_meta( $user_id, 'iweb_show_toolbar', true );
	}
}
add_filter( 'admin_init', 'iweb_show_toolbar' );