Re:TimeMachine (Score 1)

rsync can do daily hard linked backups:

create the initial backup:
rsync -a /directory/to/backup "${backup_vol}/$(date +"%Y%m%d")"

run rsync in a nightly cron job:
rsync -a --link-dest="${backup_vol}/$(date -d yesterday +"%Y%m%d")" /directory/to/backup "${backup_vol}/$(date +"%Y%m%d")"

or if you want to just link to the last backup:
rsync -a --link-dest="$(ls -d "${backup_vol}"/* | tail -1)" /directory/to/backup "${backup_vol}/$(date +"%Y%m%d")"