bash script works correctly but skips commands in cron if I am not logged in via ssh or I was connected recently

Question

I am trying to schedule some backup scripts in cron on a CentOS release 6.7 (Final).

This is the full backup, basically mounts a remote directory, checks if there is enough space available for doing the backup (it does it if the disk is at 85% or less), finally sends a mail for report and dismounts the directory

The script is located in /root/myjobs/ and its named fullbackup.sh The permissions are 777 (-rwxrwxrwx) for now

#!/bin/bash
mount -t cifs //192.168.0.202/Volume_1 /mnt/nas -o username=Backup,password=PassBackup
ocupado="$(df /mnt/nas|tail -n 1|awk '{print $4}'|cut -d "%" -f 1)"
if [ $ocupado -gt 85 ]; then
    echo "DISK IS FULL" | mail -s "SERVER" [email protected]
else
    # This is anoying but at least works, I need to create a file with the name of the backup, delete it, and then make the backup with tar
    touch /mnt/nas/Backup/full_backup_`date +"%d%b%y"`.tar.gz
    rm -f /mnt/nas/Backup/full_backup_`date +"%d%b%y"`.tar.gz
    tar -cvzpf /mnt/nas/Backup/full_backup_`date +"%d%b%y"`.tar.gz --exclude=/home/general /home
    echo "FULL BACKUP OK" | mail -s "SERVER" [email protected]
fi
umount /mnt/nas/

If I run the script manually it works fine, but if I schedule the script with cron it only sends the mail,but does not make the copy, like it does not execute the tar command.

If I execute crontab -e I see the nano editor, with this path in the top:

/tmp/crontab.jdwF9c

I think something is wrong with the path, that's why I am configuring cron editing the /etc/crontab file directly.

This is my /etc/crontab file:

SHELL=/bin/bash
PATH=/sbin:/bin:/usr/sbin:/usr/bin
MAILTO=root
HOME=/

0 9 1 * * root /root/myjobs/fullbackup.sh

I have translated this question of Spanish as best I could, I hope the problem is well understood.

Thanks for your help!

EDIT 1: I interact with the server remotely. The cron runs the script and works correctly when I'm connected, but not if I close the ssh connection and I wait for the command to run at 9:00 the next day. In that case only sends the mail.

Answer 1

Try to call tar with the full path. On my system e.g. it's /bin/tar. You can find out with which tar.