+@opsummary{level}
+@item --level=@var{n}
+Force incremental backup of level @var{n}. As of @GNUTAR version
+@value{VERSION}, the option @option{--level=0} truncates the snapshot
+file, thereby forcing the level 0 dump. Other values of @var{n} are
+effectively ignored. @xref{--level=0}, for details and examples.
+
+The use of this option is valid only in conjunction with the
+@option{--listed-incremental} option. @xref{Incremental Dumps},
+for a detailed description.
+