local $_ = $string_to_match;


my @reparts = split ' ', $re;


my $pre = '';


while (@reparts) {


    $pre .= shift @reparts;


    print "$pre w/ lookahead: ", /$pre (?=@reparts)/x, "\n";


    print "Prefix $pre: ", /$pre/x, "\n";


}


print "Shebang entier: ", /$pre/x, "\n";