Re: [gentoo-user] How to exclude a directory from rsync

[Helmut Jarausch]

On 11/25/10 22:51:36, Renat Golubchyk wrote:
> On Tue, 16 Nov 2010 23:01:51 +0000 Mick <michaelkintzios@×××××.com>
> wrote:
> > On Tuesday 16 November 2010 22:26:28 Stefan G. Weichinger wrote:
> > > Am 2010-11-16 22:24, schrieb Alan McKinnon:
> > > > Apparently, though unproven, at 23:12 on Tuesday 16 November
> > > > 2010, Mick did
> > > >
> > > > opine thusly:
> > > >> Excellent, it worked!  :-)
> > > >
> > > > Glad to hear it.
> > > >
> > > > I could help because part of my job is running a rather big
> > > > public ftp mirror that management graciously pay for. And I
> went
> > > > down this rsync road a long time ago myself.
> > > >
> > > > You have no idea how many brain cells died in agony to figure
> out
> > > > this specific piece of rsync behaviour :-)
> > >
> > > ;-)
> > >
> > > I would like to know if my suggestion also works ;-)
> > >
> > > Yeah, include/exclude-patterns are rather hard to figure out
> > > sometimes ... nearly like regexes -> write once, read never ....
> >
> > Ha, ha!  True!
> >
> > Stefan, I tried escaping the spaces (even tried \\ double and \\\
> > triple escapes in case it makes a difference because of using ssh)
> > but still did not work.  In my head I couldn't see how the full
> path
> > would not work, but the relative path would, but I tried it out all
> > the same.
> >
> > I still don't understand why Alan's recommendation works   ;-)
>
> I'm probably late with my reply, but I'll post it so it will be in
> the
> archives for future reference.
>
> The man page is actually pretty clear on this issue. Quote:
>
>   if the pattern starts with a / then it is anchored to a particular
>   spot in the hierarchy of files, otherwise it  is  matched  against
> the
>   end of the pathname.  This is similar to a leading ^ in regular
>   expressions.  Thus "/foo" would match a name of "foo" at either the
>   "root of the transfer" (for a global rule) or in the merge-file’s
>   directory (for a per-directory  rule).   An  unqualified  "foo"
> would
>   match  a  name  of "foo" anywhere in the tree because the algorithm
> is
>   applied recursively from the top down; it behaves as if each path
>   component gets a turn at being the end of the filename.  Even the
>   unanchored "sub/foo" would match  at  any  point  in  the hierarchy
>   where  a "foo" was found within a directory named "sub".
>
> "Root of the transfer" is the directory you want to sync. Thus, if
> you
> run e.g. "rsync /var/log/ /mnt/backups/ --exclude=/portage/" then
> root
> of the transfer is /var/log, and therefore the directory
> /var/log/portage will be excluded. If on the other hand you write
> --exclude=portage/ then a directory named portage anywhere in the
> tree
> under /var/log will be excluded. Without the trailing slash, i.e.
> just
> --exclude=portage any file (regular file, directory, link, whatever)
> named portage anywhere in the tree gets excluded. And finally
> --exclude=/portage would exclude a file only at the top of the tree
> that
> is going to be synchronsed.
>

Let me add some caveat which has trapped me recently.

I had (in your terms)
rsync /var/log/ /mnt/backups/ --delete --exclude=/portage/

and /var/log/portage was just a symlink to some other directory
while  /mnt/backups/portage was a real directory.
In that case rsync deletes /mnt/backups/portage !
It looks as if the "directory property" is check in the source tree
only. Quite an unpleasant surprise.

Helmut.