class RDoc::RI::Driver

def setup_pager
  return if @use_stdout
  pagers = [ENV['RI_PAGER'], ENV['PAGER'], 'pager', 'less', 'more']
  pagers.compact.uniq.each do |pager|
    next unless File.exist? pager
    io = IO.popen pager, "w" rescue next
    next if $? and $?.exited? # pager didn't work
    @paging = true
    return io
  end
  @use_stdout = true
  nil
end