findコマンド
man findより（macOS）
find 検索先のパスで列挙するのに使える
列挙するにあたり、式を評価できる
The find utility recursively descends the directory tree for each path listed, evaluating an expression (composed of the primaries and operands listed below) in terms of each file in the tree.
All operands and primaries must be separate arguments to find. Primaries which themselves take arguments expect each argument to be a separate argument to find.