A complete guide to regular expressions is rather beyond the scope of this article. However, important points to remember are that the entire pattern is treated as a regular expression, so always be careful of characters that are “special” characters in regular expressions such as .(DOT stands for any character). . (any character) * (zero of more of the preceding) + (one or more of the preceding) {} (minimum to maximum quantifier) ? (ungreedy modifier) ! (at start of string means “negative pattern”) ^ (start of string, or “negative” if at the start of a range) $ (end of string) [] (match any of contents) - (range if used between square brackets) () (group, backreferenced group) | (alternative, or) \ (the escape character itself) Flags Flags are added to the end of a rewrite rule to tell Apache how to interpret and handle the rule. They are comma-separated, and contained in square brackets. Here’s a list of the flags, with their meanings C (chained with next ...