def process_dat(filepath):
    """
    Process RNAz dat file format (generated by rnazCluster.pl

    :param filepath:
    :return:
    """
    sizes = []
    with open(filepath, 'r') as fh:
        for line in fh:
            if line.startswith('locus'):
                x = line.split()
                start = int(x[2])
                end = int(x[3])
                length = end - start
                sizes.append(length)
    return sizes
