Single config file for Vim on Windows with Cygwin
From Vim Tips Wiki
created 2005 · complexity basic · author Lee Savidge · version 5.7
I got really bored of editing multiple vimrc files when I wanted to change mine. So, after installing cygwin under Windows I added an environment variable which set HOME to be
c:\cygwin\home\username. Vim/GVim in Windows reads that variable if it is set and notes that the config file to read is the one I have in my cygwin directory. Also, because Vim/GVim under Windows understands that the config files could be called either .vimrc or _vimrc it doesn't require any other change. Now when either Vim in cygwin or Vim/GVim in Windows loads, they both use the same config files. This assumes that your config files can work under either environment as mine do.
Another option (if for some reason you don't want to change your Windows HOME var) is to create a vimrc file in your Windows home with the following lines:
set runtimepath+=c:/cygwin/home/username/.vim source c:/cygwin/home/username/_vimrc
I think if you have installed cygwin, you can use the following method: under cygwin:
$ cd ~ $ ln -s /path/to/windows/_vimrc .vimrc
and by this way, we can use the same vimrc. Don't forget we can use " if has('win32') ..." to write config for different environment.
Be careful with setting $HOME to something else under Windows. A lot of apps rely on such variable as well. You may end up messing up another app`s settings.