How to change GNOME default screen rotation

Question

How do I change the default screen rotation for my gnome desktop? Is there anyway I can change the monitor settings without logging in?

Solution

You can do so by modifying the Xorg.conf by adding the line

Section "Monitor"
     Identifier      "Monitor1"
     Option  "Rotate"        "left"
EndSection

or after login use the xrandr command as:

xrandr --output DVI-2 --rotate left

Replace DVI-2 and left as per your requirement

xrandr solution will be effective till session exist. On reboot, the changes will be lost whereas xorg.conf setting will be reboot-persistant