When editing a document in Terminal, whether it be vi or emacs or your-favorite-text-editor, you can use keyboard commands to move the cursor around.
But unless you’re an expert, the commands can be hard-to-remember and tedious. It’s also not very Mac-like. A little gem in Terminal is that you can option-click inside an editor to move your cursor to that position. In the screenshot below, my cursor was near the bottom of the view and I option-clicked right between “option-click” and “here” in the middle of the document.
Note that this works regardless of whether it’s in insert mode or not (using vi terminology). For example, when I’m in command mode in vi, I can option-click anywhere in any line and type “dd” to delete it.
A simple tip and perhaps obvious to some, but in my experience, I see people waste a lot of time arrowing around or struggle with the text navigation commands of vi and emacs when good old fashioned clicking could help you out.