When real estate shall be taken in execution by an officer, it shall be his duty to expose the same to sale at the courthouse door, having previously given twenty days’ notice of the time and place of sale, and what real estate is to be sold and where situated, by advertisement in some newspaper printed in the county which may be designated by the plaintiff or his attorney of record, if there be one regularly published, weekly or daily, and if not, by at least six printed or written handbills, signed by such sheriff, and put up in public places in different parts of the county; and the printer’s fee for such advertisement shall be taxed and paid as other costs; provided, that in all cities in this state now or hereafter containing one hundred thousand inhabitants or more, such sales shall be on the floor of the real estate exchange or at the courthouse door, as may be announced in said advertisement.