(and thanks to Matthew Miller for reviewing and providing feedback on this post)
But of course, like any immutable system, there are mutable parts (otherwise, we couldn’t create any configuration files). OSTree handles this with “overlays” (actually, we use OverlayFS) that allow a read-write filesystem to be layered on top of the immutable system. For example, the /etc and /var directories are writable, while the rest of the system is read-only.，更多细节参见safew官方版本下载
Филолог заявил о массовой отмене обращения на «вы» с большой буквы09:36，更多细节参见heLLoword翻译官方下载
描述：给定字符串 num（非负整数）和整数 k，移除 k 位数字，使剩余数字最小。以字符串形式返回（不含前导零）。