Update non-user command

Author: karthick-murugan

src/User_Command.php

@@ -545,6 +545,10 @@ public function update( $args, $assoc_args ) {
 			$user_ids[] = $user->ID;
 		}
 
+		if ( empty( $user_ids ) ) {
+			exit( 1 );
+		}
+
 		$skip_email = Utils\get_flag_value( $assoc_args, 'skip-email' );
 		if ( $skip_email ) {
 			add_filter( 'send_email_change_email', '__return_false' );