Why some commands in vim require a colon while some don't?

Question

Some of the commands in vim are given by first typing a colon (:) eg . :wq for saving a file and quitting . While some of the commands don\'t require a colon for example the Rep

Answer 1

You are in different modes of vim. There are 6 basic modes in vim. They are

1. Normal mode
2. Visual mode
3. Select mode
4. Insert mode
5. cmdLine mode
6. Ex mode

In Normal mode you don't require to type :, this mode can be reached by pressing Esc.