How do I change the cursor between Normal and Insert modes in Vim?

Question

I would like to know how to change, if possible, the cursor in Vim (in color, shape, etc.) depending on what mode you are in.

I am constantly forgetting that I am not

Answer 1

If you are using tmux and iTerm2 on macOS,
the following changes the cursor from a block to a cursor and highlights the current line

if exists('$TMUX')
  let &t_SI = "\Ptmux;\\]50;CursorShape=1\x7\\\"
  let &t_EI = "\Ptmux;\\]50;CursorShape=0\x7\\\"
else
  let &t_SI = "\]50;CursorShape=1\x7"
  let &t_EI = "\]50;CursorShape=0\x7"
endif
:autocmd InsertEnter * set cul
:autocmd InsertLeave * set nocul

credit: https://gist.github.com/andyfowler/1195581