Wordpress link pages codex

<?php link_pages( $before, $after, $next_or_number, $nextpagelink, $previouspagelink, $pagelink, $more_file ); ?> 


or

<?php
  $defaults = array(
  'before'           => '<p>' . __( 'Pages:' ),
  'after'            => '</p>',
  'link_before'      => '',
  'link_after'       => '',
  'next_or_number'   => 'number',
  'separator'        => ' ',
  'nextpagelink'     => __( 'Next page' ),
  'previouspagelink' => __( 'Previous page' ),
  'pagelink'         => '%',
  'echo'             => 1
 );
 ?>