How can I run a script that starts before my login screen?

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http://unix.stackexchange.com – I was calibrating my touch screen, and saw that the best tool around was xinput_calibrator. So I used it. It have two options (one of which did not work), so I am here for the second. It says I should execute this command "in a script that starts with your X session": xinput set-int-prop "3M 3M USB Touchscreen - EX II" "Evdev Axis Calibration" 32 14410 2146 14574 2115 So I tried ~/.xinitrc, ~/.xsession and ~/.xsessionrc, all of which did not exist. So I created them and the exact content was this command. The first two files made my logins fail (after I login, I fall back to the login screen (HowTos)