Usage of readarray and tac

I have a file containing "lines" of text, for now only two lines. I need to create a reversed array of these lines - FIFO style. Using "readarray" in this fashion works fine: readarray -t FileArray < "$PWD$DEBUG_DIR$DEBUG_MENU" When I attempt to "reverse" the file I get gibberish: readarray -t FileArray < tac "$PWD$DEBUG_DIR$DEBUG_MENU" I am still learning about substitution and it is obvious I am not using the tac command correctly. I did try different "syntax" without success.