A full-screen writing program or distraction-free editor is a text editor that occupies the full display with the purpose of isolating the writer from the operating system (OS) and other applications. Wikipedia
I wanted that with Vim. There are ways to do it. You can play with
columns to achieve this (see here). There are scripts (1, 2). But all of these seemed complicated.
Here is a simple-but-not-perfect way to achieve this. This script just hide a couple of things and add a big margin on the left:
Go fullscreen with your terminal, and enjoy:
This is quite dumb, but it works very well for me. Let me know if you find ways to improve this.