What should I write in commitinfo file for hooking my script if I want to commit an appropriate file?

Could you tell me can I add the line in commitinfo file if I want that the hook will be run if I commit an appropriate file? Example: I have *.txt file I added next line: *.txt $CVSROOT/CVSROOT/hook.sh %p %s and it is not working. What should I do ? Thanks.