#! /usr/bin/perl -w

if( !$ARGV[0] ) {
	die "Usage: $0 <file>\n";
}

open FILE, $ARGV[0] or die "Can't open $ARGV[0]: $!\n";
while(<FILE>) {
	push @old, $_;
}
close FILE;
unlink $ARGV[0];

for($i=0; $i<@old; $i++) {
	push @new, $old[$i];

	if( $i ) {
		$del=0;

		for($j=0; $j<@new-1; $j++) {
			if( !$del && $old[$i] eq $new[$j] ) { $del=1; }
		}

		if( $del ) { pop @new; }
	}
}

open FILE, ">$ARGV[0]" or die "Can't open $ARGV[0]: $!\n";
print FILE @new;
close FILE;