skeeve@Skeeves-PowerBook:~ $ perl -e '"<" =~ qr[(??{/^</})]'
Bus error
skeeve@Skeeves-PowerBook:~ $ perl -v

This is perl, v5.8.6 built for darwin-thread-multi-2level
(with 3 registered patches, see perl -V for more detail)

Copyright 1987-2004, Larry Wall

Perl may be copied only under the terms of either the Artistic License or the
GNU General Public License, which may be found in the Perl 5 source kit.

Complete documentation for Perl, including FAQ lists, should be found on
this system using `man perl' or `perldoc perl'.  If you have access to the
Internet, point your browser at http://www.perl.org/, the Perl Home Page.