Emacs

The Emacs editor of all flavors, from MicroEMACS, which I used back before I had my own UN*X system in the DOS 3 days (and for which I was a maintainer/contributor feeding fixes and features to Daniel M. Lawrence in the early 90s), to GNU Emacs, as well as Elisp.

I first got my exposure to it through Gosling Emacs, probably running on a VAX 11/780 named "ernie", probably running BSD 4.2, at The Ohio State University Computer Science Department, when I was primarily dealing with VMS, but also had accounts on the university IBM/370, on a DECSystem-20 (or was it a -10??), and a few other machines. Heck, while I try to refresh my memory, it may have even been on that DECsystem, since Emacs was available there too!  But while I thought vi was OK, really liked `EDT` (I had lots of keyboard macros for it) and thought that `TECO`, `ed`, and ex right along with the editors on Primos and DOS sucked more than the vacuum of intergalactic space, when I got my hands on Emacs, I fell in love... big time. It is part of the reason thanks to another Daniel who was a co-worker, when I found out about MicroEMACS, like him, I started using it everywhere I could, and sent lots of changes to Daniel Lawrence for inclusion into what eventually became version 3.12 (I wonder if Daniel ever recorded Dan's and my names in the contributor list...hmmm????)

But one of the features I missed in MicroEMACS, was ELisp (aka Emacs Lisp), the LISP implementation in which much of GNU Emacs is written, and in which most of its editing functionality and its macros are coded.  This is why the very first thing I did when I got my hands on a Sun 3/50 running SunOS 4 after reinstalling the OS from scratch was to download and install GNU Emacs.