Actually what your regex does is match either an asterisk, an open parentheses, a dot, or a close parentheses, (which is to say: * ) ( .) and do it one or more times. Followed by white space and then what happens to be in $1 at the time. This because the square brackets create a character class out of their contents. Please read perlre for more on character classes. Your original code was much closer to your intent, except that you would have needed to escape the asterisks in order to match literal asterisks in the text, as asterisks are meta chars. However even if you escaped them it still wouldn't work perfectly, please see death to dot star! for more.