open (OUTPUT, ">$fname.tmp");
        open (DATA, "$fname");

##</code><code>##

        open OUTPUT, '>', "$fname.tmp" or die "Cannot open '$fname.tmp' $!";
        open INPUT,  '<', $fname or die "Cannot open '$fname' $!";


##</code><code>##

        $offset = 0;
        while (read(DATA, $data, BLOCKLEN, $offset)) {
                my $blockhdr = unpack "H*", substr($data, 0, BLOCKHDR);
                my $blockdt  = unpack "H*", substr($data, BLOCKHDR, BLOCKDATA);
                my $cdrdata  = unpack "H*", substr($data, BLOCKHDR+BLOCKDATA, CDRLENGTH);
...
                        $offset += BLOCKLEN;
...
                        $offset += BLOCKLEN;
                        $offset -= 286;

##</code><code>##

                my $total_record = hextoint(reverse_str(substr($blockdt,4)));