Since I'm constantly using rsync and needing to refer to examples, here is a link to rsync examples.
10 Practical Examples of rsync Command in Linux
How to Exclude Files and Directories with Rsync
Also, here is an example of how to duplicate a (live) linux root filesystem
rsync -avP --numeric-ids --exclude='/dev' --exclude='/proc' --exclude='/sys' root@failedharddrivehost:/ /path/to/destination/