Donde manda capitán, no gobierna marinero, “where the captain commands, the sailor does not govern.” ¡Aquí mando yo!, “I am the one who commands here!” Mi palabra es la ley, “my word is the law.”
A 2005 article in Elementos, a journal of the Autonomous University of Puebla, gives the first as the form the saying has today. A 2014 article in the magazine Este País lists the other two among the phrases of a boss.