Cron how to

linux-crontab.sh

# List cron tasks for user www-data
sudo crontab -u www-data -l
# Edit cron tasks for user www-data
sudo crontab -u www-data -e

# Backup current user crontab
crontab -l > cron-backup.txt
# Restore current user crontab
crontab cron-backup.txt

# Backup user www-data crontab
crontab -u www-data -l > www-data-crontab-backup.txt
# Restore user www-data crontab
crontab -u www-data www-data-crontab-backup.txt

# Backup all users crontab (Debian)
zip -r all-users-crontab-backup.zip /var/spool/cron/crontabs
# Cron job to schedule backup of all users crontab
0 1 * * * zip -r all-users-crontab-backup.zip /var/spool/cron/crontabs
# Restore all users crontab
mv /var/spool/cron/crontabs /var/spool/cron/crontabs.backup
unzip all-users-crontab-backup.zip
cp all-users-crontab-backup /var/spool/cron/crontabs

# Jobby Cron task example
* * * * * cd /var/www/website/cron && php jobby.php 1>> /dev/null 2>&1