Binary package “pcregrep” in ubuntu-rtm 14.09
grep utility that uses perl 5 compatible regexes.
Perl-style regexps have many useful features that the standard POSIX ones
don't; this is basically the same as grep but with the different
regexp syntax.
.
The other reason for the existence of pcregrep is that its source code is an
example of programming with libpcre.