Почему нужно указывать EOF

1. Because that’s the way POSIX defines it.
2. Because some tools expect it or «misbehave» without it. For example, wc -l will not count a final «line» if it doesn’t >end with a newline.
3. Because a file (or stream) of zero lines can be distinguished from a file of one empty line.

https://stackoverflow.com/a/32782143