foreach含义：Iterates over a list and sets variable to be each element of list, performing BLOCK foreach element of list.白话文：对变量list中的所有“行”进行逐行扫描，直到全部行扫描完并执行BLOCK结束为止Formatforeach variable (list) {BLOCK}foreach unit [arg] variable (list) {BLOCK}ParametersParameterDefinitionunitcontrols how list is split into individual elementsValid Values-word assumes that the array elements are separated by white space (spaces, tabs, or \n)-line assumes that array elements are separated by \n- __single (preceded by double underscore) matches each individual occurrence of any separators from the speci