#!/usr/bin/perl
# The Missing Textutils, Ondrej Bojar, obo@cuni.cz
# http://www.cuni.cz/~obo/textutils
#
# 'skipseen' is like uniq but the lines do not need to immediately follow each
# other to be deleted. In other words: only the first occurrence of any line is
# printed.
#
# $Id: skipseen,v 1.2 2008/01/25 12:50:54 bojar Exp $
#

use strict;
my %seen;

while (<>) {
  next if $seen{$_};
  print;
  $seen{$_}=1;
}