I've be looking for a way to run a script on startup but all old threads I've found on the subject seem to be before systemd came in and none of the answers I've found seem to work anymore. I'm new to Linux operating systems and I'm not sure where to look for instructions on how to do this under systemd.
For a bit of back story I recently replaced Windows on a little tablet/laptop with Ubuntu and I've found that on start up the screen orientation is the wrong way around, meaning every time I log in I have to enter 'xrandr -o right' into the terminal, which is a bit annoying to do every time.
Additionally, if anyone has any resources for beginners entering Linux, I'd love to see them! I'm currently on a university degree and the programming side of things is all done on Ubuntu so it would be great to become more adept at using the system.
I think this two links will be helpful for you and you would be able to create your startup script: