Add a border between output and input

[logikaljay]

I am looking to achieve something like this:

1 68.45.77 user connected.
2 23.95.127 user connected.
3 114.33.134 user connected.
4 124.122.228 user connected.
5 85.206.20 user connected.
6 18.83.122 user connected.
-----------------------------------------------------------
> my prompt input

Any idea how I would achieve this?

Everything I try ends up with a mess of the input overwriting the border, or the prompt.