Riddle: What is the flattering answer of the county magistrate?

Once upon a time, there was a county magistrate with seven items. On New Year's Day, he went to the streets to watch Spring Festival couplets. Suddenly, he saw that the Spring Festival couplets posted on the door of a family were different. I saw: Part I: Counting Two Doors Part II: Earth-shattering People's Banner: The county magistrate thought: This family is so ambitious, it must be a big official of the court, so he quickly prepared a generous gift and knocked on the door to visit. The magistrate asked the host, "Which adult in your family is in Kyoto?" Hearing this, the master inexplicably claimed that all three brothers were poor. The magistrate was stupefied and asked, "What couplets are posted at the door? ... "The host replied," Ah, so that's it. " He then explained: "If you want to say that couplet, it is absolutely true." So he made a statement about the careers of his three brothers. Hearing this, the county magistrate realized that he had kowtowed to the wrong person, so he had to leave the gift and left disappointed. Can you guess the occupations of three civilian brothers? Answer: The host introduced the three brothers to sell sesame cakes and wanted to give them to customers one by one, so he said "one of the best"; The second brother is a firecracker, and he shoots "the earth shakes"; The boss is a butcher, and killing pigs does not require the approval of the yamen, so it is called "acting first".