open INFILE,  "<" . $filename 
     or die "Couldn't open file " . $filename . " for reading : $!";
open OUTFILE, ">" . $filename 
     or die "Couldn't open file " . $filename . " for writing : $!";
my %hash;
while (<INFILE>){
	print OUTFILE $_ unless $hash{$_}++;
}
close INFILE;
close OUTFILE;