Egrep
<tool> An extended version of the
Unix grep command. Egrep accepts extended regular expressions (REs) including "*" following multi-character REs; "+" (one or more matches); "?"
(zero or one matches); "|" separating two REs matches either.
REs may be bracketed with ().
Despite its additional complexity, egrep is usually faster than
fgrep or
grep.
