module Pager
  def page
    return if RUBY_PLATFORM =~ /win32/
    return unless STDOUT.tty?

    read, write = IO.pipe

    unless Kernel.fork # Child process
      STDOUT.reopen(write)
      STDERR.reopen(write) if STDERR.tty?
      read.close
      write.close
      return
    end

    # Parent process, become pager
    STDIN.reopen(read)
    read.close
    write.close

    ENV['LESS'] = 'FSRX' unless ENV['LESS']

    Kernel.select [STDIN] # Wait until we have input before we start the pager
    pager = ENV['PAGER'] || 'less'
    exec pager rescue exec "/bin/sh", "-c", pager
  rescue StandardError
  end
end