+Clear inherit attribute and reset project ID to 0 for file or directory.
+.TP
+.B -d
+Clear only the directory itself.
+.TP
+.B -r
+Clear the directory and all its descendants recursively.
+.TP
+.B ""
+If neither \fB-d\fR nor \fB-r\fR is specified, clear the directory and its
+immediate children.