filesystem supports directory indexing, or by sorting and compressing
directories for smaller directories, or for filesystems using
traditional linear directories.
+.IP
+Even without the
+.B \-D
+option,
+.B e2fsck
+may sometimes optimize a few directories --- for example, if
+directory indexing is enabled and a directory is not indexed and would
+benefit from being indexed, or if the index structures are corrupted
+and need to be rebuilt. The
+.B \-D
+option forces all directories in the filesystem to be optimized. This can
+sometimes make them a little smaller and slightly faster to search, but
+in practice, you should rarely need to use this option.
.TP
.BI \-E " extended_options"
Set e2fsck extended options. Extended options are comma