open(DAT,'<',"./useful_dat.tab")||die "Canot open file\n";
my @file=<DAT>;
close DAT;
shift @file;##remove header
foreach my $line(@file){

##</code><code>##

open(DAT,'<',"./useful_dat.tab")||die "Canot open file\n";
<DAT>;                     # discard a line
while(my $line = <DAT>){   #loop through the rest