grep /grep/ vi.
[from the qed/ed editor idiom g/re/p,
where re stands for a regular expression, to Globally search
for the Regular Expression and Print the lines containing matches
to it, via Unix grep(1)
] To rapidly scan a file or set
of files looking for a particular string or pattern (when browsing
through a large set of files, one may speak of `grepping
around'). By extension, to look for something by pattern. "Grep
the bulletin board for the system backup schedule, would you?"
See also vgrep.
[It has also been alleged that the source is from the title of a paper "A General Regular Expression Parser" -ESR]