I'm displaying the line number in front of each line, so the
tilde characters in front of non-existing lines are useless
for me. Is there a way to not display them?
While I don't think there's a way to turn them off completely,
you can set them to be the same color as the background color
with something like
:hi NonText ctermfg=black guifg=black
(assuming your default background color is black)
It does have side-effects, as it changes all "nontext", so that
includes the tildes, but also includes the 'showbreak' characters
and the continuation "@" characters, as detailed at
:help hl-NonText
Hope this helps,
-tim