This could have been one iteration off, e.g.
```fish
function on-winch --on-signal winch
echo $LINES
end
```
Resize the terminal, it'll print e.g.
24
then run `echo $LINES` interactively, it might have a different answer.
This isn't beautiful, but it works. A better solution might be to make
the termsize vars electric and just always update them on read?