rprintf(F," --fake-super store/recover privileged attrs using xattrs\n");
#endif
rprintf(F," -S, --sparse handle sparse files efficiently\n");
- rprintf(F," -n, --dry-run show what would have been transferred\n");
+ rprintf(F," -n, --dry-run perform a trial run with no changes made\n");
rprintf(F," -W, --whole-file copy files whole (without rsync algorithm)\n");
rprintf(F," -x, --one-file-system don't cross filesystem boundaries\n");
rprintf(F," -B, --block-size=SIZE force a fixed checksum block-size\n");
--super receiver attempts super-user activities
--fake-super store/recover privileged attrs using xattrs
-S, --sparse handle sparse files efficiently
- -n, --dry-run show what would have been transferred
+ -n, --dry-run perform a trial run with no changes made
-W, --whole-file copy files whole (without rsync algorithm)
-x, --one-file-system don't cross filesystem boundaries
-B, --block-size=SIZE force a fixed checksum block-size
filesystem. It doesn't seem to handle seeks over null regions
correctly and ends up corrupting the files.
-dit(bf(-n, --dry-run)) This tells rsync to not do any file transfers,
-instead it will just report the actions it would have taken.
+dit(bf(-n, --dry-run)) This makes rsync perform a trial run that doesn't
+make any changes (and produces mostly the same output as a real run). It
+is most commonly used in combination with the bf(-v, --verbose) and/or
+bf(-i, --itemize-changes) options to see what an rsync command is going
+to do before one actually runs it.
+
+The output of bf(--itemize-changes) is supposed to be exactly the same on a
+dry run and a subsequent real run (barring intentional trickery and system
+call failures); if it isn't, that's a bug. Other output is the same to the
+extent practical, but may differ in some areas. Notably, a dry run does not
+send the actual data for file transfers, so bf(--progress) has no effect,
+the "bytes sent", "bytes received", "literal data", and "matched data"
+statistics are too small, and the "speedup" value is equivalent to a run
+where no file transfers are needed.
dit(bf(-W, --whole-file)) With this option the delta transfer algorithm
is not used and the whole file is sent as-is instead. The transfer may be