| . | Matches any character. |
| [abc] | Matches a, b or c. |
| [a-z] | Matches any character a to z inclusive. |
| [^ac] | Matches any character except a and c. |
| (x) | Matches x (x might be any regexp) If used with split, this
also puts the string matching x into the result array. |
| x* | Matches zero or more occurances of 'x'
(x may be any regexp). |
| x+ | Matches one or more occurances of 'x'
(x may be any regexp). |
| x|y | Matches x or y. (x or y may be any regexp). |
| xy | Matches xy (x and y may be any regexp). |
| ^ | Matches beginning of string (but no characters). |
| $ | Matches end of string (but no characters). |
| \< | Matches the beginning of a word (but no characters). |
| \> | Matches the end of a word (but no characters). |