Yes, it does want the numbers as a file, rather than as command line arguments. If you make a numbers.txt file with all the numbers, then use numbers.txt as the only argument to your program, it does what it's supposed to.

The diamond operator <> lets you choose what to use for input in the arguments to your program. When you leave it empty, it will wait for user input. With a program like this one, it doesn't tell you that it's waiting for something, which was surprising when I did this exercise myself a couple of months ago :)