hardlinking missing files from src to a dest: didn't work way I thought it would.

[L A Walsh]

Have a directory with a bunch rpms in it, mostly x86_64.

Have another directory with a bunch, mostly 'noarch'.

Some of the noarch files are already in the x86_64 dir
and don't want to overwrite them.  They are on the same
physical disk, so really, just want the new 'noarch' files
hardlinked into the destination.

sitting in the noarch dir, I tried:
rsync -auv --ignore-existing  \
      --link-dest=/tumbleweed/. . /tumbleweed/.

I'm not "too" surprised since technically I asked for it
to synchronize them, then link them into the same dir,
but thought it would at least say something or create the
link, but neither happened.

I really didn't want to copy them -- I'd really prefer the link,
so how do I have it only create a hard link from
the source files to target DIR that don't already exist
in the target?

I know I can do it with a shell script, but I thought
rsync might be faster...then again, if I count figuring out
how to do it...not so sure....

How can I get rsync to do this?

Thanks...