[rdiff-backup-users] restoring only changed files

[Chris]

I'm doing some testing to learn how to utilise rdiff-backup. I'm hoping
some one can help answer a few questions.

I have created two directories. One is a directory called root where I
have created two files. I back those files up to a directory called
backup.

When I run "rdiff-backup -r now backup root" it tells me

"Fatal Error: Restore target root already exists, specify --force to
overwrite."

If I add --force it continues to restore all the files. The problem is I
don't need to restore all the files if some of the files haven't changed.
I only want it to restore files that I have changed. Restoring even the
files that haven't changed increases the time it takes to revert to an
older backup.

My goal is to be able rdiff-backup on a 'root partition' (root) and then
restore the files from a backup in the event my system crashes during an
apt-get upgrade.

I am working with an already slow medium. I also know that rdiff-backup is
not the fastest solution. It is probably the best solution though. I need
to 'undo' changes relatively frequently too so this is of a great concern
to me if it takes a long time to do a restore.