xdotool mousemove blank screen script question

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http://askubuntu.com – and sorry if my english is not the best i have infamouse screen going black after 10 minutes or so despite trying several solutions to avoid it in ubuntu 12.04 so i decided for the last solution which is emulating mouse move every 9 minutes i've downloaded xdotool my questions, and i guess they require simple answers (which are needed, coz i'm not really a comp freak): 1. do i have to make a script for that 2. how do i make a script and where do i save it 3. how to make it running automatically (every time computer starts), if that's not happening by default so, i want to just emulate a (HowTos)