1 打开终端，输入以下命令
sudo gedit /etc/vim/vimrc.tiny
2 进入文件后，修改 set compatible 为set nocompatible，如下所示：
" Vim configuration file, in effect when invoked as "vi". The aim of this
" configuration file is to provide a Vim environment as compatible with the
" original vi as possible. Note that ~/.vimrc configuration files as other
" configuration files in the runtimepath are still sourced.
" When Vim is invoked differently ("vim", "view", "evim", ...) this file is
" not sourced; /etc/vim/vimrc and/or /etc/vim/gvimrc are.
" Debian system-wide default configuration Vim
set runtimepath=~/.vim,/var/lib/vim/addons,/usr/share/vim/vimfiles,/usr/share/vim/vim82,/usr/share/vim/vimfiles/after,/var/lib/vim/addons/after,~/.vim/after
set nocompatible
" vim: set ft=vim:
3 保存退出。进入vi编辑器，按i，即可看到"Insert"，说明进入了输入模式。