[ih] ed, ex & vi (unix text editor)

[the keyboard of geoff goodfellow]

"... History and influence

The ed text editor was one of the first three key elements of the Unix
operating system—assembler, editor, and shell—developed by Ken Thompson in
August 1969 on a PDP-7 at AT&T Bell Labs.[2] Many features of ed came from
the qed text editor developed at Thompson's alma mater University of
California, Berkeley.[4] Thompson was very familiar with qed, and had
reimplemented it on the CTSS and Multics systems. Thompson's versions of
qed were notable as the first to implement regular expressions. Regular
expressions are also implemented in ed, though their implementation is
considerably less general than that in qed.

Dennis M. Ritchie produced what Doug McIlroy later described as the
"definitive" ed,[5] and aspects of ed went on to influence ex, which in
turn spawned vi. The non-interactive Unix command grep was inspired by a
common special use of qed and later ed, where the command g/re/p performs a
global regular expression search and prints the lines containing matches.
The Unix stream editor, sed implemented many of the scripting features of
qed that were not supported by ed on Unix.[6]...

https://en.wikipedia.org/wiki/Ed_(text_editor)

-- 
Geoff.Goodfellow at iconia.com
living as The Truth is True