:q! is to save and overread existing permissions (usually used by root)

In vi to

- save to file you do :w

- save and exit you do :wq

- save, exit and override permissions :wq! (usually root)

Check out this tutorial on using vi. I'd actually recommend getting used to using it because of the power and the fact that you can always find it on any *nix distribution (AFAIK)