.	
 
 
 Any single character except a newline
^	
 
 
 The beginning of the line or string
$	
 
 
 The end of the line or string
*	
 
 
 Zero or more of the last character
+	
 
 
 One or more of the last character
?	
 
 
 Zero or one of the last character

a.x	
 
 
 a followed by ONE character then x 
^w	
 
 
 w at the beginning of a line
^wag	
 
 
 wag at the beginning of a line
x$	
 
 
 x at the end of a line
xyz$	
 
 
 xyz at the end of a line
xyd*	
 
 
 xy followed by zero or more d characters
.*	
 
 
 Any string without a newline
	 
^$	
 
 
 A line with nothing in it.

[xyz]		
 
 
 Either x or y or z
[^xyz]		
 
 
 Neither x nor y nor z
[a-z]		
 
 
 Anything from a to z inclusive
[^a-z]		
 
 
 No lower case letters
[a-zA-Z]	
 
 
 Any letter
[a-z]+		
 
 
 Any non-zero sequence of lower case letters

abc|xyz	
 
 
 Either abc or xyz
(ab|xy)il	
 
 
 Either abil or xyil
(ax)+		
 
 
 Either ax or axax or axaxax or...

\n		
 
 
 A newline
\t		
 
 
 A tab
\w		
 
 
 Any alphanumeric (word) character.
		The same as [a-zA-Z0-9_]
\W		
 
 
 Any non-word character.
		The same as [^a-zA-Z0-9_]
\d		
 
 
 Any digit. The same as [0-9]
\D		
 
 
 Any non-digit. The same as [^0-9]
\s		
 
 
 Any whitespace character: space,
		 tab, newline, etc
\S		
 
 
 Any non-whitespace character
\b		
 
 
 A word boundary, outside [] only
\B		
 
 
 No word boundary

\|		
 
 
 Vertical bar
\[		
 
 
 An open square bracket
\)		
 
 
 A closing parenthesis
\*		
 
 
 An asterisk
\^		
 
 
 A carat symbol
\/		
 
 
 A slash
\\		
 
 
 A backslash



We use regular expressions for matching. Put them in /.../ slashes	

Square brackets are used to match any character inside them. 
Inside: "-" means "between" and  "^" at the beginning means "not".

To mach really the characters  $, |, [, ), \, / , we preceed them by 
a backslash:\.