linux桌面下打开终端，vim/vi file.py
按照下面步骤键入字母执行操作，注意 “:”
- Esc – switch to command mode.
- :w – write out changes that were made.
- :q – exit Vim.
- :q! – exit Vim and discard any changes.
- :wq – saves the changes, and exits Vim.
- : x – save the changes made, and exits Vim.