Motherfucking ed

$ ed letter_to_prog.txt
P
*i
Why aren't you using ed, the standard text editor? It only has a few commands, it's on every Unix OS available, and let's you focus on what you're writing. Much better that vim and emacs. Both of them are bloated and therefore are shit.
.
*w
*q

>>4
Ok. I challenge you and everyone else to implement ed on lisp of your choice. Perfect /prog/ challenge to celebrate 0x7DC.