if($. != 1){
  # we're not on the first page
  # "make 'previous' link" code
}
if($. != 1 && $. != $total_number_of_lines){
  # we're not on the first or last page
  # add neat little " | " to separate
  # my 'next' and 'last' links
}

if($. != $total_number_of_lines){
  # we're not on the last page
  # "make 'next' link" code
}