my $regexp = 'hello.*world';

if( /$regexp/ ) {
    print "Your regexp '$regexp' matches '$_'\n";
    for my $match ( 0..$#- ) {
        print sprintf "Match %02d (%d, %d):\t[%s]\n", $match, $-[$match], $+[$match], substr( $_, $-[$match], $+[$match] );
    };
};