Time Machine uses Access Control Lists (ACLs) for advanced permissions. Two such permissions are:

时间机器有两种权限类型
● You cannot use the "rm" terminal command to delete backups items. As noted above, delete files from within the Time Machine application or delete a consolidated backup folder.

你不能使用“rm”命令在终端使用删除命令。可以在时间机器应用程序中删除文件，或者直接删除整理过的备份文件夹
● You do not have write access to backup items. If you want to change a file, change the original, not the backup.

你对备份的文件没有写的权限。如果你想改变文件，你只能改变原始文件，不能改变备份文件