Within vi if you can't exit /etc/vim/vimrc you can type
:syntax off
And to turn it back on:
:syntax on
Many of us have a dark/black background in our terminal/shell making the default syntax unreadable, the solution is to either turn off syntax highlighting with :syntax off or to enable a special option in /etc/vim/vimrc
Edit /etc/vim/vimrc
The "syntax on" enables the highligh........