DELTREE and hidden, system, and read-only attributes
The DELTREE command deletes all files contained in a directory or
subdirectory, regardless of attributes.
If DELTREE successfully deleted the directory, it returns an ERRORLEVEL
value of 0.
Using wildcards with DELTREE
You can use wildcards with the DELTREE command, but use them with extreme
caution. If you specify a wildcard that matches both directory names and
filenames, both the directories and files will be deleted. Before specifying
wildcards with the DELTREE command, use the DIR command to view the files
and directories you will delete.