Thanks again for all your help.
No matter which path I use the error message always states ./synology.sh
Tomorrow i will try using the rule/rules.
EDIT:
Well, the error message came from a broken thing, which I could not delete/modify. It did not come from my script/s.
Problem however is that I still cannot run the command due to missing rights. I guess the problem is described here:
https://community.openhab.org/t/solved-executecommandline-script-issue/31767/3
Openhab is not running the commands as user openhabian, but as user openhab
Now I will try to set up keys for user openhab so it is possible for openhab to login to the synology. Or I try to run the command as user openhabian
Actually my script only consists of 1 line, so I might be able to run that as another user…
ssh -p xxx openhab@192.168.178.xx sudo poweroff