Most Linux administrators know about cron, but modern Linux systems also include another powerful scheduling option: systemd timers. A systemd timer lets you run a script on a schedule using the same management framework you already use for services. That means you can start, stop, enable, disable, inspect, log, and troubleshoot scheduled jobs with familiar systemctl and journalctl commands.
The Basic Pattern
A scheduled systemd job normally has three parts: a script that does the work, a .service unit that runs the script, and a .timer unit that schedules the service.
1. A script that does the work.
2. A .service unit that runs the script.
3. A .timer unit that schedules the service.
Step 1: Create a Script
sudo vi /usr/local/sbin/example-job.sh
Add the following script:
#!/bin/bash
LOGFILE="/var/log/example-job.log"
{
echo
"============================================================"
echo "Example job started:
$(date)"
echo "Hostname:
$(hostname)"
echo "This is where the
scheduled work would happen."
echo "Example job finished:
$(date)"
echo
"============================================================"
echo
} >> "$LOGFILE"
exit 0
Make the script executable:
sudo chmod 750
/usr/local/sbin/example-job.sh
sudo chown root:root /usr/local/sbin/example-job.sh
Test the script manually before involving systemd:
sudo /usr/local/sbin/example-job.sh
sudo tail -n 20 /var/log/example-job.log
Step 2: Create the systemd Service
sudo vi /etc/systemd/system/example-job.service
Create the following service unit:
[Unit]
Description=Run the example scheduled job
[Service]
Type=oneshot
ExecStart=/usr/local/sbin/example-job.sh
Reload systemd and test the service:
sudo systemctl daemon-reload
sudo systemctl start example-job.service
systemctl status example-job.service
journalctl -u example-job.service -n 50
Step 3: Create the systemd Timer
sudo vi /etc/systemd/system/example-job.timer
Create the timer unit:
[Unit]
Description=Run the example scheduled job once per day
[Timer]
OnCalendar=*-*-* 07:00:00
Persistent=true
Unit=example-job.service
[Install]
WantedBy=timers.target
This timer runs the script once per day at 7:00 AM local server time. Persistent=true means the job will run later if the system was powered off during the scheduled time.
Step 4: Enable and Start the Timer
sudo systemctl daemon-reload
sudo systemctl enable --now example-job.timer
Check the timer and view the next scheduled run:
systemctl status example-job.timer
systemctl list-timers --all | grep example-job
Step 5: Test and Troubleshoot
To manually run the scheduled job immediately:
sudo systemctl start example-job.service
To view logs from the service:
journalctl -u example-job.service -n 100
journalctl -u example-job.service -f
To stop the timer temporarily:
sudo systemctl stop example-job.timer
To disable the timer permanently:
sudo systemctl disable --now example-job.timer
Common OnCalendar Examples
|
Schedule |
OnCalendar Value |
|
Every day at 7:00 AM |
*-*-* 07:00:00 |
|
Every hour |
hourly |
|
Every Monday at 1:00 AM |
Mon *-*-* 01:00:00 |
|
Every day at midnight |
daily |
|
Every 15 minutes |
*:0/15 |
Final Thoughts
systemd timers provide a clean and modern way to schedule recurring jobs on Linux. Unlike cron, timers integrate directly with systemctl and journalctl, making them easier to manage, troubleshoot, and monitor. Once you understand the pattern of script, service, and timer, you can apply it to backups, antivirus scans, maintenance tasks, monitoring scripts, and many other server administration jobs.
References
freedesktop.org. systemd.timer: Timer unit configuration. https://www.freedesktop.org/software/systemd/man/systemd.timer.html
freedesktop.org. systemd.service: Service unit configuration. https://www.freedesktop.org/software/systemd/man/systemd.service.html
freedesktop.org. systemctl: Control the systemd system and service manager. https://www.freedesktop.org/software/systemd/man/systemctl.html
