7.1.5. Example of a Weekly Full Backup Followed by Daily Incremental Backups
A Weekly Full Backup Followed by Daily Incremental Backups
The script makes a full backup on a Sunday and incremental backups of the following days. Each day that a backup is made, a new subdirectory is created. This script requires a daily cron job.
so
if [[ $(date +%w) == 0 ]]; then
should be
if [[ $(date +%w) == 7 ]]; then