| \xFF | Character 0xFF | |
\n \r \t | LF, CR and TAB respectively |
| \a \e \f \v | BELL, ESC, FEED, Vertical TAB respectively | |
\cA ... \cZ | ASCII Control+A ... Control+Z |
| [abz] | a, b or c | |
[\^\]\\\-] | ^, \, - or ] |
| [a-zA-Z0-9] | Any letter or digit | |
[^a-d] | Any character except a, b, c or d |
| \d, \w and \s | Digits, Words and whitespace | |
\D, \W and \S | Negated versions of the above. |
| [\b] | Backspace character | |
. (dot) | Any single character except line break |
| ^ (caret) | Start of the string | |
$ (dollar) | End of the string |
| abc|def|xyz | abc, def or xyz | |
abc(def|xyz) | abcdef or abcxyz |
| abc? | ab or abc | |
* (star) | Repeats zero or more times |
| + (plus) | Repeats one or more | |
a{3}b{4} | aaabbbb |
| a{2,4} | aa, aaa or aaaa | |
a{2,} | Matches 2 or more "a"s |