--size-only skip files that match in size
--modify-window=NUM compare mod-times with reduced accuracy
-T, --temp-dir=DIR create temporary files in directory DIR
+ -y, --fuzzy find similar file for basis if no dest file
--compare-dest=DIR also compare received files relative to DIR
--copy-dest=DIR ... and include copies of unchanged files
--link-dest=DIR hardlink to files in DIR when unchanged
transferred on the receiving side. The default behavior is to create
the temporary files in the receiving directory.
+dit(bf(-y, --fuzzy)) This option tells rsync that it should look for a
+basis file for any destination file that is missing. The current algorithm
+looks in the same directory as the destination file for either a file that
+has an identical size and modified-time, or a similarly-named file. If
+found, rsync uses the fuzzy basis file to try to speed up the transfer.
+
+Note that the use of the bf(--delete) option might get rid of any potential
+fuzzy-match files, so either use bf(--delete-after) or specify some
+filename exclusions if you need to prevent this.
+
dit(bf(--compare-dest=DIR)) This option instructs rsync to use em(DIR) on
the destination machine as an additional hierarchy to compare destination
files against doing transfers (if the files are missing in the destination