egrep

from The Free On-line Dictionary of Computing (8 July 2008)

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}.

   (2004-07-20)

from V.E.R.A. -- Virtual Entity of Relevant Acronyms (June 2006)

EGREP
       Extended Global Regular Expression Print (Unix, GREP)