On Wed, 2007-11-07 at 00:08 -0500, [EMAIL PROTECTED] wrote:
> Then how about this: If your patch winds up in rsync, it requires a
> patch to the manpage entry for -n that says, essentially, "You can't
> trust the actual information emitted when running with -n to match
> what gets emitted if you haven't specified -n. Therefore, if you're
> writing things that parse rsync's output, you must ensure that your
> script works with and without -n. Here is an itemization of those
> things that might be different in its output with and without -n:
> (a) With -n, the speedup line will be omitted.
> (b) ....?"
> Etc.
My proposed omission of the speedup would be far from the first
difference in output between dry and real runs. In any event, the man
page description of --dry-run needs some serious work. I propose the
attached patch, which even comes with a commit message:
Improve the man page and --help descriptions of --dry-run. In particular,
make it clear that --dry-run turns off action without turning on verbosity,
and mention some statistics that are meaningless on a dry run.
Matt
Improve the man page and --help descriptions of --dry-run. In particular,
make it clear that --dry-run turns off action without turning on verbosity,
and mention some statistics that are meaningless on a dry run.
--- old/options.c
+++ new/options.c
@@ -351,7 +351,7 @@ void usage(enum logcode F)
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 skip actual modifications to destination\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");
--- old/rsync.yo
+++ new/rsync.yo
@@ -352,7 +352,7 @@ to the detailed description below for a
--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 skip actual modifications to destination
-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
@@ -1022,8 +1022,19 @@ NOTE: Don't use this option when the des
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 go through the motions of a copy
+(and produce mostly the same output) but skip the actual modifications to
+the destination. It is most commonly used in combination with bf(--verbose)
+and/or bf(--itemize-changes) 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" is meaningless.
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
--
To unsubscribe or change options: https://lists.samba.org/mailman/listinfo/rsync
Before posting, read: http://www.catb.org/~esr/faqs/smart-questions.html
