Ed (text Editor) - History and Influence

History and Influence

The editor was originally written in PDP-11/20 assembler in 1971 by Ken Thompson. Many features of ed came from the qed from his alma mater University of California at Berkeley Thompson was very familiar with qed, and had reimplemented it on the CTSS and Multics systems. His versions of qed were the first to implement regular expressions. Although regular expressions are part of ed, their implementation is considerably less general than that in qed.

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 uses of qed and later ed, where the command g/re/p means globally search for the regular expression re and print the lines containing it. The Unix stream editor, sed implemented many of the scripting features of qed that were not supported by ed on Unix. In turn sed influenced the design of the programming language AWK - which inspired aspects of Perl.