ReGex

regex-examples.txt

[^] ;Not these chars 

[][] ;Sequence of options 

[]{n,m} ;n-m repetition of options 

. ;Any char 

[]+ ;At least one of 

[]* ;0 or more of 

[]? ;0 or 1 

\ ;escape 

^ ;Line beginning 
$ ;Line end 

() ;Capture (can be nested) 
$1 refers to first capture

(|) ;OR (can be nested 

[:alnum:]
;[A-Za-z0-9]	
;alnum, digit, punct, alpha, graph, space, blank, lower, upper, cntrl, print, xdigit
;https://en.wikibooks.org/wiki/Regular_Expressions/POSIX_Basic_Regular_Expressions#Character_classes
[[:<:]]
;and `[[:>:]]' ;match the null string at the beginning and end of a word (sequence of alnum or _) respectively.

;;A `\Q' sequence causes literal (``quote'') mode to be entered, while `\E' ends literal mode, and returns to normal regular expression processing.

;;ENHANCED FEATURES
\<  Matches the null string at the beginning of a word.  This is equivalent to `[[:<:]]'.
\>  Matches the null string at the end of a word.  This is equivalent to `[[:>:]]'.
\b  Matches the null string at a word boundary (either the beginning or end of a word).
\B  Matches the null string where there is no word boundary.  This is the opposite of `\b'.
\t  The ``horizontal-tab'' character (ASCII code 9).
\s ;Whitespace
\S ;Non whitespace 
\d ;Digit
\D ;Non digits 
\w ;Any alphanumeric 
\W ;Non alphanumeric 
\r  The ``carriage-return'' character (ASCII code 13).
\n  The ``new-line/line-feed'' character (ASCII code 10).