Editing Ed (software) (section)

== History and influence ==
The ed text editor was one of the first three key elements of the Unix operating system—[[Assembly language#Assembler|assembler]], [[Line editor|editor]], and [[Unix shell|shell]]—developed by [[Ken Thompson]] in August 1969 on a [[PDP-7]] at [[AT&T Bell Labs]].<ref name="penguin"/>  Many features of ed came from the [[QED (text editor)|qed]] text editor developed at Thompson's [[alma mater]] [[University of California, Berkeley]].<ref>D. M. Ritchie and K. L. Thompson, "QED Text Editor", [https://wayback.archive-it.org/all/20150203071645/http://cm.bell-labs.com/cm/cs/who/dmr/qedman.pdf MM-70-1373-3] (June 1970), reprinted as "QED Text Editor Reference Manual", MHCC-004, Murray Hill Computing, Bell Laboratories (October 1972).</ref> Thompson was very familiar with qed, and had reimplemented it on the [[Compatible Time-Sharing System|CTSS]] and [[Multics]] systems. Thompson's versions of qed were notable as the first to implement [[regular expression]]s. 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,<ref name="reader">{{cite tech report |first1=M. D. |last1=McIlroy |author-link1=Doug McIlroy |year=1987 |url=https://www.cs.dartmouth.edu/~doug/reader.pdf |title=A Research Unix reader: annotated excerpts from the Programmer's Manual, 1971–1986 |series=CSTR |number=139 |institution=Bell Labs}}</ref> and aspects of ed went on to influence [[Ex (text editor)|ex]], which in turn spawned [[Vi (text editor)|vi]].  The non-interactive Unix command [[grep]] was inspired by a common special use of qed and later ed, where the command <code>g/re/p</code> performs a '''g'''lobal '''r'''egular '''e'''xpression search and '''p'''rints the lines containing matches.  The Unix stream editor, [[sed]] implemented many of the scripting features of [[QED (text editor)|qed]] that were not supported by ed on Unix.<ref>{{Cite web |last=Raymond |first=Eric |date=2003 |title=The Art of Unix Programming |url=https://nakamotoinstitute.org/static/docs/taoup.pdf |url-status=live |archive-url=https://web.archive.org/web/20230615012711/https://nakamotoinstitute.org/static/docs/taoup.pdf |archive-date=June 15, 2023 |access-date=June 14, 2023}}</ref>{{failed verification|date=June 2023}}<ref name=early_history>
{{cite web
| title = On the Early History and Impact of Unix
| url = http://www.columbia.edu/~rh120/ch001j.c11
| quote = "A while later a demand arose for another special-purpose program, gres, for substitution: g/re/s. Lee McMahon undertook to write it, and soon foresaw that there would be no end to the family: g/re/d, g/re/a, etc. As his concept developed it became sed…"
}}
</ref>