I found myself context switching back and forth between my terminal and ChatGPT, so I wrote a very simple CLI to talk to the ChatGPT model directly from your terminal. It's not free (uses your API key) but the costs are basically de minimis.

There are quite a few other similar CLI's, but this is the only one that I'm aware of which implements streaming completions and has zero external dependencies (self-contained build, OS-agnostic).