I moved about 20 gigs of data from one server to another but i cant sit with it all night... during the night though files are going to change so how would I resync all this data? I used scp to move everything but can rsync be used to move data from source to destination without having to wait another 7 hours again and without it changing anything on the source server.. If so how

yes, rsync will compare the source files and the destination files and move only the ones that are different.

Is it user specific or just checks what you tell it to? Some files are owned by different users so another words

I could do this, write a bash script to

SRC="someipaddress"

rsync -av --copy-unsafe-links -H -e ssh --delete root@$SRC:/home/username /home/
rsync -av --copy-unsafe-links -H -e ssh --delete root@$SRC:/var/lib/mysql /var/lib

Yes?