%data_hash = ();
open(IFH,"<data.txt") or die();
while(<IFH>){ $data_hash{(split /,/ , $_)[0]} = $_;}
close(IFH);
open(OFH, ">data.txt" );
for(sort {$b <=> $a} keys %data_hash){print OFH $data_hash{$_};}
close OFH;