def fixed_length_fields(module, output):
    """Parse output string lists(rows) of lists(cols) by fixed length

    Output will be a large string with embedded new line characters.
    Each line will have a fixed set of fields of a certain length as
    specified by `module.params['field_length']`

    Results will be a list of lists such as:

    [['%CPU', 'USER', 'COMMAND'], ['0.0', 'root', '/sbin/init'], ...]
    """

    length = module.params['field_length']
    output = output.rstrip()  # We need spacing; don't strip from left
    rows = []
    for line in output.split('\n'):
        fields = []
        while line:
            fields.append(line[:length].strip())
            line = line[length:]
        rows.append(list(fields))
    return rows