| REGULAR EXPRESSIONS |
| . | = | match any character |
| ^ | = | beginning of a line |
| $ | = | end of a line |
| [[:<:]] | = | beginning of a word |
| [[:>:]] | = | end of a word |
| xy|z | = | match xy OR z |
| x? | = | match zero or one x character |
| x* | = | match zero or more x characters |
| x+ | = | match one or more x characters |
| x{3} | = | match x three times |
| x{3,} | = | match x three or more times |
| x{3,5} | = | match x three to five times |
| [xyz] | = | match x, y OR z |
| [^abc] | = | exclude x, y AND z |
| [:class:] | = | match a character class, i.e.: |
| | [:alpha:] for letters |
| | [:digit:] for numbers/digits |
| | [:space:] for white space |
| | [:punct:] for punctuation |
| | [:upper:] for upper-case letters |