“The ability to make outlines, or to view any structured
document in an outline view, are touted features of Microsoft Word
and just about every word processor out there. Linux has its ways
here, too. The Vim editor has folding, and Emacs has Outline mode,
which lets you selectively view documents by their main headings.
You can hide and view the text under headings, move quickly between
headings, and easily mark whole branches of the outline for
cutting.“Turn on Outline mode for a particular Emacs buffer by running
the commandEsc x outline-mode…”