And, as the regex manual pages tell us: "To include a literal ']' in the list, make it the first character (following a possible '^'). Note that you must always specify the first number of a range (i.e., ".]" matches exactly any of the characters inside the brackets). There are at least two b's ("abb", "abbbb", etc.)įrom three to five b's ("abbb", "abbbb", or "abbbbb") Matches a string that has an a followed by exactly two b's ("abb") You can also use bounds, which appear inside braces and indicate ranges in the number of occurrences: Matches any string ending with "ab", "abb", "abbb" etc. There might be a single b or not ("ac", "abc" but not "abbc").Ī possible 'a' followed by one or more 'b's at the end of the string: Same, but there's at least one b ("abc", "abbc", etc., but not "ac") Matches a string that has an a followed by zero or more b's ("ac", "abc", "abbc", etc.) What they mean is: "zero or more", "one or more", and "zero or one." Here are some examples: In addition, the symbols '*', '+', and '?', denote the number of times a character or a sequence of characters may occur. You can see that if you don't use either of these two characters, you're saying that the pattern may occur anywhere inside the string - you're not "hooking" it to any of the edges. Matches a string that ends in with "of despair".Ī string that starts and ends with "abc" - effectively an exact match comparison.Ī string that has the text "notice" in it. Matches any string that starts with "The". These symbols indicate the start and the end of a string, respectively:
For a complete description please visit ^' and '$'įirst of all, let's take a look at two special symbols: '^' and '$'. There follows some very basic examples of regular expression usage. Regular Expressions can be extremely complex but they are very flexible and powerful and can be used to perform comparisons that cannot be done using the other checks available. Regular Expression can be used in Content Filter conditions.
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