Create a simple systemd service unit file and run a script on boot

SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Server 12

A script is needed to run on boot. With SUSE Linux Enterprise Server 12 and above, a systemd service unit file is needed. There are MANY parameters you can add, but here is the most simple version of a unit file:

Here is a very simple script to run. For this basic setup we create a simple script that runs once and then is done as part of the boot process. For this example the script is in /usr/sbin/. The script needs to be marked executable.

server1:/root/ # ls -lah /usr/sbin/example.sh
-rwxr-xr-x 1 root root 58 Jul 24 14:14 /usr/sbin/example.sh

server1:/root/ # cat /usr/sbin/example.sh
#!/bin/bash
echo "the script works" >> /tmp/diditwork.txt

Next create a systemd service unit file named test.service. Please note you want this to be in /etc/systemd/system/ and NOT in /usr/lib/systemd/ or it could be written over on the next update.

The key thing to change is the path to your script in your environment. ExecStart=/bin/bash /usr/sbin/example.sh   (The example script created above is /usr/sbin/example.sh)       

server1:/etc/systemd/system # cat /etc/systemd/system/test.service
[Unit]
Description=example systemd service unit file.

[Service]
ExecStart=/bin/bash /usr/sbin/example.sh

[Install]
WantedBy=multi-user.target

NOTE: Depending on the intention, it may be desired to add the "Type=oneshot" option at the start of the [Service] section. The default with the above example would be "Type=simple", basically changing this determines how a service is handled. All the possible options available and their influence on a systemd service however goes beyond the scope of this TID, for additional details see the systemd.service man page.

To reload systemd with this new service unit file, run:

systemctl daemon-reload

Finally to start the script on boot, enable the service with systemd:

systemctl enable test.service

After a reboot, the service file ran the script. The script wrote the output correctly to the output file:

server1:/root/ # cat /tmp/diditwork.txt
the script works

For complete documentation about systemd services, please visit systemd service documentation .