You don't use programs that have Undo?
Ed doesn't have undo.
Ed is for those who can remember what they are working on. If you are an idiot, you should use Emacs. If you are an Emacs, you should not be vi. If you use ED, you are on THE PATH TO REDEMPTION. THE SO-CALLED “VISUAL” EDITORS HAVE BEEN PLACED HERE BY ED TO TEMPT THE FAITHLESS. DO NOT GIVE IN!!! THE MIGHTY ED HAS SPOKEN!!!
ED IS THE TRUE PATH TO NIRVANA! ED HAS BEEN THE CHOICE OF EDUCATED AND IGNORANT ALIKE FOR CENTURIES! ED WILL NOT CORRUPT YOUR PRECIOUS BODILY FLUIDS!! ED IS THE STANDARD TEXT EDITOR! ED MAKES THE SUN SHINE AND THE BIRDS SING AND THE GRASS GREEN!!
When I use an editor, I don't want eight extra KILOBYTES of worthless help screens and cursor positioning code! I just want an EDitor!! Not a “viitor”. Not a “emacsitor”. Those aren't even WORDS!!!! ED! ED! ED IS THE STANDARD!!! TEXT EDITOR.
When IBM, in its ever-present omnipotence, needed to base their “edlin” on a Unix standard, did they mimic vi? No. Emacs? Surely you jest. They chose the most karmic editor of all. The standard.