I need to know is it possible to rotate the orientation of all X-based apps to 90 degrees. Without modifying their sources. I guess X11 should have some configuration option for this. So how to do this ?
Found the answer myself.
xrandr -o left will rotate display orientation to left. xrandr -o right will rotate display orientation to right. xrandr -o inverted will invert display orientation xrandr -o normal will set to normal mode.