Invention of ed

The program ed is a line-oriented text editor for Unix, written by Ken Thompson at Bell Labs in the earliest days of the system. It was created on a PDP-7 and based on earlier editors such as QED, adding regular expressions for searching and substitution. Because users of early terminals edited files by commands typed one line at a time, ed offered compact commands for printing, changing and moving lines. It remains part of the POSIX standard. Its commands and syntax influenced later tools, including ex and vi, the stream editor sed and the search tool grep, whose name comes from the ed command that prints lines matching a regular expression.

Open on the timeline