Hey guys, sorry for just getting back with you now.
Unfortunately, I am just now recovering from a self-inflicted computer
disaster.
While fighting with rsync, I did either:
sudo rsync -aAXHSxvv --delete --info=progress2,stats2,name2
/media/default/MSD1/ /media/default/MSD2
or
sudo rsync -aAXHxvv --delete --info=progress2,stats2,name2
/media/default/MSD1/ /media/default/MSD2/
Just one small problem: MSD2 was not connected to my computer!
(Don't say it . . . )
Instead of giving an error message, rsync just created a directory on my
computer called /media/defaultMSD2, and filled it up until my / partition
was full, and THEN my desktop environment (Cinnamon) popped up a
notification saying so. How thoughtful.
The computer then would not reboot into the operating system.
No problem, I say. I will just use Timeshift to restore from its backup of
a few hours earlier.
But that did not work, even after deleting the extra directory, and trying
restores from multiple Timeshift backups.
Anyway, I never could fix the problem. But I did take it as an opportunity
to "start over". I put in a new(er) SSD, and did a fresh install, replacing
Cinnamon with Gnome. Mistake - now I remember why I dislike Gnome, ever
since Gnome 3. Wish I had re-installed Cinnamon, but too late now, out of
time. For now I will just have to grit my teeth and live with it.
[BTW, yes, I do have all of my data. Backfilling it into my new setup will
no doubt be an ongoing adventure.]
Anyway, just a few notes about the rsync situation:
1) Having or not having a trailing / on the destination directory did not
seem to make any difference in the size of the copy made, or otherwise.
Nevertheless, I intend to heed the advice given to have a trailing / after
both source and destination, or neither, as appropriate.
2) Using or not using an "S" option with rsync did not seem to make any
difference, at least concerning the size of the copy made.
3) Yes, I really should check into using checksums to avoid "bot rot".
Good advice.
Finally, Gnome sucks. (Did I mention that?)
Thanks for the replies.