I'm a beginning Vim user. I hate pressing the Esc key, which is a little far on my T61. In order to return to command mode. How do I map it to F4?
For a single session, you could just enter the following keystrokes exactly:
esc:imapspace<f4>space<esc>enter
The esc key ensures that you're in command mode, colon starts a line command, and the imap maps the F4 key to ESCAPE.
However, if you want this retained for every session, you'll need to put in in your Vim start-up file.
The location of this varies depending on your environment (for my Linux box, it's at $HOME/.gvimrc for gvim, $HOME/.vimrc for vim). You'll need to find it and add the line:
imap <f4> <esc>
One trick you can use is to start a naked Vim session (vim without an argument) then enter
:e $MYVIMRC
which will open up your current start-up file.
Also,
:echo $HOME
should tell you the location of it under Windows.
Just like many Emacs users rebind their "Caps Lock" key to "Control", vimmers rebind their "Caps Lock" to "Escape".
...At least I do. And it works wonders.
Another way to exit insert mode is to use Ctrl+C. Not sure whether that helps in your situation though.
Try home row:
imap jj <Esc>
imap <F4&> <ESC>
来源：https://stackoverflow.com/questions/764569/map-esc-key-in-vim