using external file explorer
http://midnight-commander.org/
Then config it to use external editor vim
For open all files in one vim, one may open a vim server
vim --servername server_name_here
then open in other location
vim --servername server_name_here --remote file_name_here
One can get all lines:
vim --servername server_name_here --remote-expr "getline(1,'$')"
One can issue commands:
vim --servername server_name_here --remote-send "<ESC>"
Through –remote-expr and –remote-send, one could almost totally control the vim server.