ed (text editor) 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.
Features of ed include: - available on