One of my favorite but little used emacs features is rectangular editing. It's little used because I don't need it all that often. It's one of my favorites because when I do need it, it's just so amazingly useful.

The idea is you can mark a rectangle of text, cut it and later paste it. This means that if you have three columns of text:

a b c
d e f
g h i
j k l

You can easily mark the middle column (b e h k) or even just the b e and h, cut it and paste it elsewhere as a rectangle. You can also open up a rectangular region (filled with whitespace). There are a couple of other niceties but that's the basic idea.

Here's a link to all the functions:

https://www.gnu.org/software/emacs/manual/html_node/emacs/Rectangles.html

And the video:

Enjoy. Relevant links:

• Video series overview page:
• http://cestlaz.github.io/stories/emacs
• Code:
• https://github.com/zamansky/using-emacs/tree/master