Using rsync to delete a single file
Try this:
rsync -rv --delete --include=foo.txt '--exclude=*' /home/user/ user@remote:/home/user/
(highly recommend running with --dry-run
first to test it) Although it seems like it would be easier to use ssh...
ssh user@remote "rm /home/user/foo.txt"
That's a bit trivial, but if, like me, you came to this page looking for a way to delete the content of a directory from remote server using rsync, this is how I did it:
Create an empty mock folder:
mkdir mock
Sync with it:
rsync -arv --delete --dry-run ~/mock/ remote_server:~/dir_to_clean/
Remove
--dry-run
from the line above to actually do the thing.