def count_uniquelymapping_reads(self, file_name, paired_end):
        """
        Counts the number of reads that mapped to a unique position.

        :param str file_name: name of reads file
        :param bool paired_end: This parameter is ignored.
        """
        param = " -c -F256"
        if file_name.endswith("sam"):
            param += " -S"
        return self.samtools_view(file_name, param=param)