#!/usr/bin/perl

if ($ARGV[0] eq 'line')
{
  print "Line-at-a-time\n";
  while (<STDIN>)
  {
    print
      if /perl/;
  }
}
else
{
  print "All at once\n";
  my @arr = (<STDIN>);
  foreach (@arr)
  {
    print
      if /perl/;
  }
}