display glitches after rotate

[Robin Paulson]

i'm using a couple of very simple (one line each) shell scripts in
2008.9 to manually change the screen orientation. problem is, after
the rotation is done, there are lots of artifacts, covering about a
quarter of the screen.

i can get rid of them by tapping anywhere on the desktop, but since i
have so many icons, this is getting difficult

is there a command i can run from bash, and hence put in my shell
scripts, that will force the screen to refresh and remove the
glitches?

i don't want to use the rotate C programme, i find it's too
inconsistent relying on the accelerometers to do this

thanks