---

tags:

• automation
• linux
• sysadmin

---

Linux crontab

• https://crontab.guru/
• https://crontab.guru/every-1-minute
• https://github.com/ghdrako/doc_snipets/wiki/linux-cron

Syntax

MIN HOUR DOM MON DOW CMD

Check Cron Daemon Status

sudo systemctl status cron
sudo systemctl status crond

Simulate cron’s environment by clearing your environment variables

env -i /bin/bash --noprofile --norc -c "/path/to/your_script.sh"

Redirect Output and Errors

*/10 * * * * /path/to/your_script.sh >> /path/to/log_$(date +'\%Y-\%m-\%d').log 2>&1  # nie dziala 
*/10 * * * * /path/to/your_script.sh >> /path/to/log_$(date -I).log 2>&1 # dziala

Check the Cron Logs

/var/log/cron  # redhat
tail -f /var/log/cron

List not commented crontab jobs

crontab -l | grep -v -E '^[:space:](/ghdrako/doc_snipets/wiki/:space:)*#'
crontab -l | sed '/^[:space:](/ghdrako/doc_snipets/wiki/:space:)*#/d'