Am I the only person who still uses ed occasionally?
(And for those folks who think code bloat is relevant ...
$ size /bin/ed
text data bss dec hex filename
42160 2300 0 44460 adac /bin/ed
$ size /bin/vi
text data bss dec hex filename
692378 27796 13884 734058 b336a /bin/vi
$ size /usr/bin/emacs
text data bss dec hex filename
2033257 4692020 0 6725277 669e9d /usr/bin/emacs
)
Another advantage of ed is that you can run it on a teletype ... or the dumbest of dumb terminals.