| . | 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) |
Note that \ can be used to quote these characters in which case they match themselves, nothing else. Also note that when quoting these something in Pike you need two \ because Pike also uses this character for quoting.
For more information about regexps, refer to your unix manuals such as sed or ed.
Descriptions of all functions in /precompiled/regexp follows: