Because vi is built on top of the ex line editor, you get all the power of a line editor as well. Any experienced vi user issues ex commands all the time - but usually one by one, at the colon prompt.
The one exception is the, which is, at bottom, a list of commands for ex to run on startup - in short, an editor script.
What many beginners don't know is that you can save a sequence of ex commands in any file, and execute it with the. For example, Bruce Barnett uses this trick to set himself up specially for .
:so is most often used for reading in setup commands.
mind though; any time you find yourself issuing the same
commands over and over again, think script!