How keys was defined in terminal

This had never been a issue until I give up vimr and use kitty + neovim. I found that my <S-Fn> no longer works.

Well, do panic, use infocmp or keybind or keycode to find out how the key is defined (also can use cat or sed -n -l). For kitty <S-F1> key code is ^[[1;2P . Here ^[ means <Esc> or \E

vim and neovim handle key code slight different.

for neovim, S-Fn was map to F(12+n) , e.g. S-f1 mapped to F13. So you can do this:

    map <F13> <S-F1>

vim is slightly different. :help keycode

    set <S-F1>=^[[1;2P
    map <Esc>[1;2P <S-F1>

So put it all together

if !has("gui_running")
  if !has('nvim')
    set <S-F1>=^[[1;2P
    map <Esc>[1;2P <S-F1>
    set <S-F2>=^[[1;2Q
    map <Esc>[1;2Q <S-F2>
    set <S-F3>=^[[1;2R
    map <Esc>[1;2R <S-F3>
  else
    map <F13> <S-F1>
    map <F14> <S-F4>
    map <F15> <S-F5>
    map <F16> <S-F6>
  endif
endif