+The .rsync_argvs file contains a command-line suitable for updating a
+destination tree using that batch update fileset. It can be executed
+using a Bourne(-like) shell, optionally passing in an alternate
+destination tree pathname which is then used instead of the original
+path. This is useful when the destination tree path differs from the
+original destination tree path.
+
+Generating the batch update fileset once saves having to perform the
+file status, checksum and data block generation more than once when
+updating multiple destination trees. Multicast transport protocols can
+be used to transfer the batch update files in parallel to many hosts at
+once, instead of sending the same data to every host individually.
+
+Example:
+
+verb(
+$ rsync --write_batch=pfx -a /source/dir/ /adest/dir/
+$ rcp pfx.rsync_* remote:
+$ rsh remote rsync --read_batch=pfx -a /bdest/dir/
+# or alternatively
+$ rsh remote ./pfx.rsync_argvs /bdest/dir/
+)
+
+In this example, rsync is used to update /adest/dir/ with /source/dir/
+and the information to repeat this operation is stored in the files
+pfx.rsync_*. These files are then copied to the machine named "remote".
+Rsync is then invoked on "remote" to update /bdest/dir/ the same way as
+/adest/dir/. The last line shows the rsync_argvs file being used to
+invoke rsync.
+
+Caveats:
+
+The read-batch option expects the destination tree it is meant to update
+to be identical to the destination tree that was used to create the
+batch update fileset. When a difference between the destination trees
+is encountered the update will fail at that point, leaving the
+destination tree in a partially updated state. In that case, rsync can
+be used in its regular (non-batch) mode of operation to fix up the
+destination tree.
+
+The rsync version used on all destinations should be identical to the
+one used on the original destination.
+
+The -z/--compress option does not work in batch mode and yields a usage
+error. A separate compression tool can be used instead to reduce the
+size of the batch update files for transport to the destination.
+
+The -n/--dryrun option does not work in batch mode and yields a runtime
+error.
+
+See bf(http://www.ils.unc.edu/i2dsi/unc_rsync+.html) for papers and technical
+reports.
+
+manpagesection(SYMBOLIC LINKS)
+
+Three basic behaviours are possible when rsync encounters a symbolic
+link in the source directory.
+
+By default, symbolic links are not transferred at all. A message
+"skipping non-regular" file is emitted for any symlinks that exist.
+
+If bf(--links) is specified, then symlinks are recreated with the same
+target on the destination. Note that bf(--archive) implies
+bf(--links).
+
+If bf(--copy-links) is specified, then symlinks are "collapsed" by
+copying their referent, rather than the symlink.
+
+rsync also distinguishes "safe" and "unsafe" symbolic links. An
+example where this might be used is a web site mirror that wishes
+ensure the rsync module they copy does not include symbolic links to
+bf(/etc/passwd) in the public section of the site. Using
+bf(--copy-unsafe-links) will cause any links to be copied as the file
+they point to on the destination. Using bf(--safe-links) will cause
+unsafe links to be ommitted altogether.
+