Hello and thanks for this very useful tool!

When you backup /, the SRC_FOLDER var is stripped of the last / (line 378), and the df call (line 411) writes "df: '': No such file or directory" to STDERR. The script continues with the backup but it is not cron friendly since it always writes to STDERR and you cannot do:

MAILTO=panos@example.com
0 */1 * * * rsync_tmbackup.sh / /mnt/backup >/dev/null

and only expect emails when something unexpected happens. It will always send an email due to the df error.

Best regards,

Panos