I would like to add this command "systemctl suspend-then-hibernate" to a key-combination (ALT+s). For some unknow reason it ask for permission, but it doesn't ask for "systemctl hibernate" or "systemctl suspend". What might be the reason? I also checked sudoers. Adding this doesn't help. I am not sure how this commands operate - don't find anything in the /etc path. Can someone give me a hint? In best case I would replace "suspend" by this "suspend-then-hibernate" also in powermanager, e.q. for close-lid. Thank you (Running ubuntu mate 18.04)
Can answer the first part: The addition in /etc/sudoers was wrong. I don't clearly understand the difference but adding this line to /etc/sudoers.d/myfile helps.
The question howto replace the default suspend by suspend-then-hibernate is still open.