Linux.com: Vim Tips: Using Viewports

“A lot of folks use Vim, but many exploit only a small
percentage of the editor’s features. Sure, you might know how to do
the basics in Vim, but what about using more advanced features such
as folding, split windows, and marks? With a little practice, you
can really boost your productivity with Vim.

“In this and future articles, I’m going to cover Vim features
that you may not be familiar with if you’re a casual Vim user. If
you’re confident using Vim to edit configuration files or make
short edits in text files, but maybe not too comfortable with
undertaking major writing or coding in Vim, then these articles
should be for you…”