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In Regrlar Expresions, there are three special characters that are used in matching patterns:

1. "^" - a caret is called an "anchoring operator," and matches the beginning of a string. The caret may also mean "not," which is at best confusing.
2. "$" - a dollar sign is another anchoring operator and matches only the end of a string.
3. "." - the period matches anything and is called the "match any character" operator. Many would call this a "wildcard" match character.
4. + matches one or more repetitions of the preceding RE
5. * matches zero or more repetitions of the preceding RE
6. ? matches zero or one repetition of the preceding RE