$ date; perl -e'"aaaaaaaaaaaaaaaaaaaaaa" =~ /a?a?a?a?a?a?a?a?a?a?a?a?a?a?a?a?a?a?a?a?a?a?[b]/;'; date
Mon Mar 17 16:44:46 PDT 2008
Mon Mar 17 16:44:54 PDT 2008

$ date; perl -e'alarm(1); "aaaaaaaaaaaaaaaaaaaaaa" =~ /a?a?a?a?a?a?a?a?a?a?a?a?a?a?a?a?a?a?a?a?a?a?[b]/;'; date
Mon Mar 17 16:45:02 PDT 2008
Alarm clock
Mon Mar 17 16:45:03 PDT 2008