The actual string EOF it is an indication string that helps you to understand that is the end of your file. ... I prefer reading files line by line ... [emphasis added]

I think it's important to point out that the EOF identifier as used in the OPed code example has nothing to do with the end-of-file condition or reading an entire file into an array. Rather, it is an arbritrary identifier defined to mark the end of a here document. (I think you understand this perfectly well since you use the THANOS identifier in exactly this way in the code example you give, but I want to clarify this point for any novice monk who might happen upon this thread. :)