| 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) |
