“grep was written to find text in a hand written document from the 1800s”
“the original grep was written in PDP-11 assembly language”
“Let me add one thing,” Kernighan remembers with a laugh. Twenty-five years ago, in the spring of 1993, he’d been teaching as a visiting professor and needed an assignment for his programming class. So he provided his students the source code for ed — “It was at that time probably 1800 lines of C” — and told them to do what Ken Thompson did.
“Your job is to take these 1800 lines of C and convert them into grep, as a C program. And you’ve got a week to do it.”
(See also previous topics: Unix Tell All Book From Kernighan Hits The Shelves and Brian Kernighan interviews Ken Thompson at VCF East)