def readable_timestamp(stamp):
    """
    :param stamp: A floating point number representing the POSIX file timestamp.
    :return: A short human-readable string representation of the timestamp.
    """
    if date.fromtimestamp(stamp) == date.today():
        return str(datetime.fromtimestamp(stamp).strftime("%I:%M:%S%p"))
    else:
        return str(date.fromtimestamp(stamp))
:param stamp: A floating point number representing the POSIX file timestamp.
    :return: A short human-readable string representation of the timestamp.