>355
これでどうでしょうか?動作確認はしておりませんが...

if ( $ENV{'QUERY_STRING'} eq $read_data[1] ){
    open(DATA, $datatext);
    while (<DATA>){
        @read_data = split(/\t/);
        $read_data[2]++;
        push(@lastdata, join("\t", @read_data)."\n");
    }
    close DATA;
    open(WRITE,">$datatext");
    print WRITE @lastdata;
    close WRITE;
    print qq(<META HTTP-EQUIV="Refresh" CONTENT="0;URL=$ENV{'QUERY_STRING'}">\n);
    exit;
}