| Predefined term | Matches |
| \t | Horizontal tab |
| \b | Backspace |
| \v | Vertical tab |
| \f | Form feed |
| \r | Carriage return |
| \n | Newline |
| \cA : \cZ | Control characters |
| \x0000 : \xFFFF | Unicode hexadecimal |
| \x00 : \xFF | ASCII hexadecimal |
| . | Any character, except for newline (\n) |
| \d | Any decimal digit; equivalent to [0-9] |
| \D | Any character but a decimal digit; equivalent to [^0-9] |
| \w | Any alphanumeric character including underscore; equivalent to [A-Za-z0-9_] |
| \W | Any character but alphanumeric and underscore characters; equivalent to [^A-Za-z0-9_] |
| \s | Any whitespace character (space, tab, form feed, and so on) |
| \S | Any character but a whitespace character |
| \b | A word boundary |
| \B | Not a word boundary (inside a word) |
原文：http://www.cnblogs.com/undefined000/p/5450313.html