Okay, I am having some trouble with this script. Everything appears okay till the last line (which is incomplete).
It would help if I had the rest of the script to review -- I am running it on a test system with fake directories and files to see just how it performs. Note: If /u1/ops is a seperately mounted partition you might want to look at replacing tar with dump -- as dump will let you do incremental backups (like you said you only want to backup what has changed).
In the meantime... what is the rest of the script... starting with the rest of the last line.