rsync is an open source utility that provides fast incremental file transfer. rsync is freely available under the GNU General Public License and is currently being maintained by Wayne Davison.

Here is a script of do incremental backup by rsync. Hope it can help you.
Test OS:Centos4,5 RedHatAS4,5

#!/bin/sh

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# Script to do incremental rsync backups
# Adapted from script found on the rsync.samba.org
# Jason 3/24/2002
# This script is freely distributed under the GPL
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# Configure These Options… Read the rest