head-like

The feature head-like provides a flag like --lines' of [head`(1)](https://www.man7.org/linux/man-pages/man1/head.1.html).

-n/--lines as we known it can be abbreviated to -number, it looks like:

head -9 some.txt.file   # print the first 9 lines of 'some.txt.file'

head-like app simulate it with:

go run ./examples/head-like -n 9
go run ./examples/head-like --lines 9
go run ./examples/head-like -9
go run ./examples/head-like -113