An eXtended version of the UniXgrep 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)