my %first;
while (<$one>) {
 chomp;
 my @data = split /\t/;
 $first{$data[0]}=$data[1]; # fill the hash with the values from the first file
}
close $one;

while (<$two>) {
 chomp; # just search the hash for these strings
 exists $first{$_} && print $foutname $first{$_},'\n';
}
close $two;
close $foutname || warn "$fout: $!\n';