#!/usr/local/bin/perl
# Jaime Prilusky, 2009

  my $s4 = shift @ARGV || "the";
  $string = join(" ",@ARGV) || 
qq{There were doors all round the hall, but they were all locked; and when Alice 
had been all the way down one side and up the other, trying every door, she walked
sadly down the middle, wondering how she was ever to get out again.};

  while ($string =~ m/$s4/g) {  # try also with 'i' as modifier
    reportHit(pos($string),$`,$&,$');
  }

sub reportHit {
  ($pos,$bef,$hit,$aft) = @_;
  print qq{
POS:$pos
$bef>>>$hit<<<$aft
};
  return;
}